新型功能材料高压性质的第一性原理研究
|
摘要
随着高新技术的不断发展和进步,出现了许多新的功能材料,对这些新型功能材料的研究受到了广泛的关注。压力作为一个重要的热力学参数,对于调节材料的物理性能能起到重要的作用。基于此,研究压力对新型功能材料结构和物理性质的影响对于我们更好地了解和改善材料的性能以及设计和合成具有良好应用前景的新材料都将起到重要的作用。本文运用第一性原理计算方法对几种新型功能材料的高压性质进行了研究。全文共分为八章。
第一章介绍了对新型功能材料高压性质进行研究的研究背景和意义;回顾了本文所关注的几种新型功能材料的研究现状。
第二章首先简单介绍了采用赝势平面波表述的第一性原理计算方法的基本原理。其次,对相变基本理论进行了介绍,其中重点关注的是相变的分类、压致相变的特点和高压相的理论预测方法。
第三章对NaBH_4在高压下的结构相变进行了研究。本文的计算首次从理论上证实了NaBH_4高压相的BaSO_4型结构,并正确的预测到了实验上观察到的从β-NaBH_4(P42_(1c))到γ-NaBH_4(BaSO_4-type, Pnma)的相变,计算得到的相变压力(9.66 GPa)与Kumar等人通过X射线衍射实验得到的结果(8.9 GPa)符合较好。最后,我们的研究还表明常温下实验上发现的从β-NaBH_4到γ-NaBH_4的高压相变在低温下也能够完成,从而在一定程度上解决了以往理论计算和实验结果间的分歧。
第四章研究了Mg_2X(X=C, Si, Ge, Sn)在高压下的结构相变、电子结构和光学性质。对结构相变的研究表明,在压力作用下Mg_2X(X=C, Si, Ge, Sn)将经历从反萤石结构到反氯化铅结构,再到Ni_2In型结构的两次结构相变。对Mg_2C而言,从反萤石结构到反氯化铅结构的相变是一级相变,而从反氯化铅结构到Ni_2In型结构的相变没有发现体积突变是二级相变。对Mg_2Si,Mg_2Ge和Mg_2Sn来说,两次高压结构相变都是一级相变。四种材料在由反氯化铅结构转变到Ni_2In型结构的相变过程中,反氯化铅结构Mg_2X(X=C, Si, Ge, Sn)的晶格常数的变化表现出了明显的非线性特征,这种现象可以认为是相变的前导。对电子结构的研究表明,Mg_2C的带隙宽度会随压力的增加而增加,与之相反Mg_2Si,Mg_2Ge和Mg_2Sn的带隙宽度会随压力的增加而减小,后三种材料在高压下表现出了金属的性质。对光学性质的研究表明,四种材料的光学性质会随压力的增加而急剧变化。对Mg_2C而言,压力作用下介电函数虚部ε2的吸收峰会随着带隙宽度的增加而往高能级方向移动。而对Mg_2Si,Mg_2Ge和Mg_2Sn来说,在高压下ε2的谱线中出现了许多新的吸收峰。
第五章研究了压力对CaMgX(X=Si, Ge, Sn)结构稳定性和电子结构的影响。通过理论计算我们成功地预测到了三种材料在压力作用下从pnma结构到Ni_2In型结构的连续相变。对电子结构的研究表明,常压下pnma结构的CaMgSi和CaMgGe表现出半金属的性质;而pnma结构的CaMgSn则表现出了金属的性质。压力的作用将导致CaMgSi和CaMgGe发生从半金属到金属的电子结构的转变。而CaMgSn的电子结构对压力不敏感,其主要变化是能带宽度随压力的增大不断增加。
第六章从理论上对实验上观察到的TiS_2高压相的结构作出了预测。结果表明,TiS_2将经历一次从1T结构到氯化铅结构的一级压致相变。计算得到的相变压力为16.20 GPa,与实验上测得的20.7 GPa的相变压力符合较好。与常压下的1T结构相比,高压下氯化铅结构的TiS_2有更紧凑的结构和更大的体变模量。另外,我们还对TiS_2的电子结构进行了研究。结果表明从1T结构到氯化铅结构的压致相变伴随着从半金属到金属的电子结构的转变。
第七章对晶化BeF2的高压相变进行了研究,发现在50 GPa的压力范围内,BeF_2将先后经历从α-石英型结构到柯石英型结构,再到金红石型结构,最后到α-PbO2型结构的三次结构相变;对各种结构的BeF_2的电子结构进行了比较,发现其电子结构对特定的晶体类型并不敏感,其电子结构主要由晶体中的BeF_4四面体结构(或BeF_6八面体结构)决定。
第八章是全文研究工作的总结和对下一步研究工作的展望。
With the development of science and technology, many new functional materials emerged. For its extensive use, new functional materials have attracted intensively attention in recent years. It is well known that pressure is an important parameter to tune physical properties. High-pressure research on new functional materials is now helping us to better understand and improve the physical properties of materials and providing useful information in the design and synthesis of new materials. In the present study, high-pressure properties of several new functional materials are investigated by using first-principles calculation method. The whole thesis is divided into eight chapters.
In chapter 1, the background and significance of the high-pressure research on new functional materials are briefly introduced, and then the recent research progresses of several new functional materials studied in this thesis are reviewed.
In chapter 2, a brief introduction to the first-principles calculation methods based on plane wave functions and pseudopotential is given firstly. Then the phase transition theory are introduced, such as the classification of phase transition, the features of pressure-induced phase transition and the methods for crystal structure prediction of high-pressure phases.
In chapter 3, the pressure induced structural transition of NaBH_4 fromβ-NaBH_4 (P421c) toγ-NaBH_4 (BaSO_4-type, Pnma) is investigated. The BaSO_4-type structure of high-pressure phase is testified theoretically for the first time. The calculated transition pressure is 9.66 GPa and agrees reasonably well with the experimental results (~8.9 GPa). Our results correctly predict the experimental observed phase transition fromβ-NaBH_4 toγ-NaBH_4 and demonstrate that this high-pressure transition may occur at low temperature. The poor agreement between previous theoretically prediction and experimental results have been settled in a certain extend.
In chapter 4, the phase transitions, electronic structures and optical properties of Mg_2X (X=C, Si, Ge, Sn) under high pressure are investigated. The calculated results demonstrate that Mg_2X (X=C, Si, Ge, Sn) undergo two pressure-induced phase transitions from the anti-fluorite to anti-cotunnite and then from the anti-cotunnite to the Ni_2In-type structures. For Mg_2Si, Mg_2Ge and Mg_2Sn, the two high-pressure phase transitions are first-order. While, for Mg_2C, the previous phase transition is first-order and the later is second-order. When approaching the phase transition, the changes of lattice parameters of the anti-cotunnite Mg_2X (X=C, Si, Ge, Sn) show noticeable nonlinearities. This can be considered as a precursor of the phase transition. The electronic structure calculations show that the band gaps of Mg_2C become broader with the increase of the pressure. But for Mg_2Si, Mg_2Ge and Mg_2Sn, the reverse is true. The results show that they have become metallic at high pressure. Finally, the imaginary and real parts of the dielectric function for different structures Mg_2X (X=C, Si, Ge, Sn) are calculated. The results show that the optical properties of Mg_2X (X=C, Si, Ge, Sn) change drastically with increasing pressure.
In chapter 5, the pressure effects on the structural stabilities and electronic properties of CaMgX (X=Si, Ge, Sn) are discussed. Our results successfully predict a continuous phase transition from pnma to Ni_2In-type structure for CaMgX (X=Si, Ge, Sn). In addition, we discuss the electronic structures of both the pnma and Ni_2In-type CaMgX (X=Si, Ge, Sn). At ambient pressure, the pnma structure CaMgSi and CaMgGe display semimetal behaviors and the pnma structure CaMgSn displays metal behaviors. At high pressure, a semimetal to metal electronic transition is found for CaMgSi and CaMgGe. While, for CaMgSn, the electronic structures are found to be quite insensitive to pressure, the significant changes are the bands become broader at high pressure.
In chapter 6, a theoretical investigation on the structural stabilities and electronic properties of TiS_2 under high pressures has been performed. The results show that TiS_2 undergoes a first-order pressure-induced phase transition from its 1T-type structure to cotunnite-type structure. The calculated transition pressure 16.20 GPa agrees quite well with the experimental finding (20.7 GPa). Compared with 1T-type structure, the cotunnite-type high-pressure phase has a more compact structure with a large bulk modulus. In addition, we discussed the electronic structures of TiS_2. Our results suggest that the structural phase transition of TiS_2 from 1T-type to cotunnite-type structure at high pressure is followed by a semimetal to metal electronic transition.
In chapter 7, high-pressure behaviors of BeF_2 are investigated theoretically. The results demonstrate that the sequence of the pressure-induced phase transitions of BeF_2 under 50 GPa is from theα-quartz, to coesite, rutile, andα-PbO2-type structures. Moreover, the electronic properties of different crystal structures BeF_2 are compared. The results show that the electronic structures of BeF_2 are fairly insensitive to the particular crystal structures, which determined mainly by the BeF4 tetrahedron (or BeF6 octahedra).
In chapter 8, the contents of this dissertation are summarized and future directions of research are given.
第一章介绍了对新型功能材料高压性质进行研究的研究背景和意义;回顾了本文所关注的几种新型功能材料的研究现状。
第二章首先简单介绍了采用赝势平面波表述的第一性原理计算方法的基本原理。其次,对相变基本理论进行了介绍,其中重点关注的是相变的分类、压致相变的特点和高压相的理论预测方法。
第三章对NaBH_4在高压下的结构相变进行了研究。本文的计算首次从理论上证实了NaBH_4高压相的BaSO_4型结构,并正确的预测到了实验上观察到的从β-NaBH_4(P42_(1c))到γ-NaBH_4(BaSO_4-type, Pnma)的相变,计算得到的相变压力(9.66 GPa)与Kumar等人通过X射线衍射实验得到的结果(8.9 GPa)符合较好。最后,我们的研究还表明常温下实验上发现的从β-NaBH_4到γ-NaBH_4的高压相变在低温下也能够完成,从而在一定程度上解决了以往理论计算和实验结果间的分歧。
第四章研究了Mg_2X(X=C, Si, Ge, Sn)在高压下的结构相变、电子结构和光学性质。对结构相变的研究表明,在压力作用下Mg_2X(X=C, Si, Ge, Sn)将经历从反萤石结构到反氯化铅结构,再到Ni_2In型结构的两次结构相变。对Mg_2C而言,从反萤石结构到反氯化铅结构的相变是一级相变,而从反氯化铅结构到Ni_2In型结构的相变没有发现体积突变是二级相变。对Mg_2Si,Mg_2Ge和Mg_2Sn来说,两次高压结构相变都是一级相变。四种材料在由反氯化铅结构转变到Ni_2In型结构的相变过程中,反氯化铅结构Mg_2X(X=C, Si, Ge, Sn)的晶格常数的变化表现出了明显的非线性特征,这种现象可以认为是相变的前导。对电子结构的研究表明,Mg_2C的带隙宽度会随压力的增加而增加,与之相反Mg_2Si,Mg_2Ge和Mg_2Sn的带隙宽度会随压力的增加而减小,后三种材料在高压下表现出了金属的性质。对光学性质的研究表明,四种材料的光学性质会随压力的增加而急剧变化。对Mg_2C而言,压力作用下介电函数虚部ε2的吸收峰会随着带隙宽度的增加而往高能级方向移动。而对Mg_2Si,Mg_2Ge和Mg_2Sn来说,在高压下ε2的谱线中出现了许多新的吸收峰。
第五章研究了压力对CaMgX(X=Si, Ge, Sn)结构稳定性和电子结构的影响。通过理论计算我们成功地预测到了三种材料在压力作用下从pnma结构到Ni_2In型结构的连续相变。对电子结构的研究表明,常压下pnma结构的CaMgSi和CaMgGe表现出半金属的性质;而pnma结构的CaMgSn则表现出了金属的性质。压力的作用将导致CaMgSi和CaMgGe发生从半金属到金属的电子结构的转变。而CaMgSn的电子结构对压力不敏感,其主要变化是能带宽度随压力的增大不断增加。
第六章从理论上对实验上观察到的TiS_2高压相的结构作出了预测。结果表明,TiS_2将经历一次从1T结构到氯化铅结构的一级压致相变。计算得到的相变压力为16.20 GPa,与实验上测得的20.7 GPa的相变压力符合较好。与常压下的1T结构相比,高压下氯化铅结构的TiS_2有更紧凑的结构和更大的体变模量。另外,我们还对TiS_2的电子结构进行了研究。结果表明从1T结构到氯化铅结构的压致相变伴随着从半金属到金属的电子结构的转变。
第七章对晶化BeF2的高压相变进行了研究,发现在50 GPa的压力范围内,BeF_2将先后经历从α-石英型结构到柯石英型结构,再到金红石型结构,最后到α-PbO2型结构的三次结构相变;对各种结构的BeF_2的电子结构进行了比较,发现其电子结构对特定的晶体类型并不敏感,其电子结构主要由晶体中的BeF_4四面体结构(或BeF_6八面体结构)决定。
第八章是全文研究工作的总结和对下一步研究工作的展望。
With the development of science and technology, many new functional materials emerged. For its extensive use, new functional materials have attracted intensively attention in recent years. It is well known that pressure is an important parameter to tune physical properties. High-pressure research on new functional materials is now helping us to better understand and improve the physical properties of materials and providing useful information in the design and synthesis of new materials. In the present study, high-pressure properties of several new functional materials are investigated by using first-principles calculation method. The whole thesis is divided into eight chapters.
In chapter 1, the background and significance of the high-pressure research on new functional materials are briefly introduced, and then the recent research progresses of several new functional materials studied in this thesis are reviewed.
In chapter 2, a brief introduction to the first-principles calculation methods based on plane wave functions and pseudopotential is given firstly. Then the phase transition theory are introduced, such as the classification of phase transition, the features of pressure-induced phase transition and the methods for crystal structure prediction of high-pressure phases.
In chapter 3, the pressure induced structural transition of NaBH_4 fromβ-NaBH_4 (P421c) toγ-NaBH_4 (BaSO_4-type, Pnma) is investigated. The BaSO_4-type structure of high-pressure phase is testified theoretically for the first time. The calculated transition pressure is 9.66 GPa and agrees reasonably well with the experimental results (~8.9 GPa). Our results correctly predict the experimental observed phase transition fromβ-NaBH_4 toγ-NaBH_4 and demonstrate that this high-pressure transition may occur at low temperature. The poor agreement between previous theoretically prediction and experimental results have been settled in a certain extend.
In chapter 4, the phase transitions, electronic structures and optical properties of Mg_2X (X=C, Si, Ge, Sn) under high pressure are investigated. The calculated results demonstrate that Mg_2X (X=C, Si, Ge, Sn) undergo two pressure-induced phase transitions from the anti-fluorite to anti-cotunnite and then from the anti-cotunnite to the Ni_2In-type structures. For Mg_2Si, Mg_2Ge and Mg_2Sn, the two high-pressure phase transitions are first-order. While, for Mg_2C, the previous phase transition is first-order and the later is second-order. When approaching the phase transition, the changes of lattice parameters of the anti-cotunnite Mg_2X (X=C, Si, Ge, Sn) show noticeable nonlinearities. This can be considered as a precursor of the phase transition. The electronic structure calculations show that the band gaps of Mg_2C become broader with the increase of the pressure. But for Mg_2Si, Mg_2Ge and Mg_2Sn, the reverse is true. The results show that they have become metallic at high pressure. Finally, the imaginary and real parts of the dielectric function for different structures Mg_2X (X=C, Si, Ge, Sn) are calculated. The results show that the optical properties of Mg_2X (X=C, Si, Ge, Sn) change drastically with increasing pressure.
In chapter 5, the pressure effects on the structural stabilities and electronic properties of CaMgX (X=Si, Ge, Sn) are discussed. Our results successfully predict a continuous phase transition from pnma to Ni_2In-type structure for CaMgX (X=Si, Ge, Sn). In addition, we discuss the electronic structures of both the pnma and Ni_2In-type CaMgX (X=Si, Ge, Sn). At ambient pressure, the pnma structure CaMgSi and CaMgGe display semimetal behaviors and the pnma structure CaMgSn displays metal behaviors. At high pressure, a semimetal to metal electronic transition is found for CaMgSi and CaMgGe. While, for CaMgSn, the electronic structures are found to be quite insensitive to pressure, the significant changes are the bands become broader at high pressure.
In chapter 6, a theoretical investigation on the structural stabilities and electronic properties of TiS_2 under high pressures has been performed. The results show that TiS_2 undergoes a first-order pressure-induced phase transition from its 1T-type structure to cotunnite-type structure. The calculated transition pressure 16.20 GPa agrees quite well with the experimental finding (20.7 GPa). Compared with 1T-type structure, the cotunnite-type high-pressure phase has a more compact structure with a large bulk modulus. In addition, we discussed the electronic structures of TiS_2. Our results suggest that the structural phase transition of TiS_2 from 1T-type to cotunnite-type structure at high pressure is followed by a semimetal to metal electronic transition.
In chapter 7, high-pressure behaviors of BeF_2 are investigated theoretically. The results demonstrate that the sequence of the pressure-induced phase transitions of BeF_2 under 50 GPa is from theα-quartz, to coesite, rutile, andα-PbO2-type structures. Moreover, the electronic properties of different crystal structures BeF_2 are compared. The results show that the electronic structures of BeF_2 are fairly insensitive to the particular crystal structures, which determined mainly by the BeF4 tetrahedron (or BeF6 octahedra).
In chapter 8, the contents of this dissertation are summarized and future directions of research are given.
引文
[1]郑昌琼,冉均国.新型无机材料.北京:科学出版社, 2003, 1-8
[2]周馨我.功能材料学.北京:北京理工大学出版社, 2009, 1-2
[3]贡长生,张克立.新型功能材料.北京:化学工业出版社, 2001, 1-6
[4] Trimarchi G, Zunger A. Global space-group optimization problem: finding the stablest crystal structure without constraints. Phys. Rev. B, 2007, 75(10): 104113
[5] Ogitsu T. Computational physics: a quantum puzzle revisited. Nature Phys., 2007, 3(7): 452-453
[6] Pickard C J, Needs R J. Structure of Phase III of solid hydrogen. Nature Phys., 2007, 3(7): 473-476
[7] Oganov A R, Glass C W. Evolutionary crystal structure prediction as a tool in material design. J. Phys.: Condens. Matter, 2008, 20(6): 064210
[8] Behler J, Martoňák R, Donadio D, et al. Metadynamics simulations of the high-pressure phases of silicon employing a high-dimensional neural network potential. Phys. Rev. Lett., 2008, 100(18):185501
[9] McMillan P F. New materials from high-pressure experiments. Nature Mater., 2002, 1(1): 19-25
[10] Gregoryanz E, Sanloup C, Somayazulu M, et al. Synthesis and characterization of a binary noble metal nitride. Nature Mater., 2004, 3(5): 294-297
[11] Horvath-Bordon E, Riedel R, Zerr A, et al. High-pressure chemistry of nitride-based materials. Chem. Soc. Rev., 2006, 35(10): 987-1014
[12] He J L, Guo L C, Guo X J, et al. Predicting hardness of dense C3N4 polymorphs. Appl. Phys. Lett., 2006, 88(10): 101906
[13] Oguchi H, Matsuo M, Hummelsh?J J S, et al. Experimental and computational studies on structural transitions in the LiBH4-Lil pseudobinary system. Appl. Phys. Lett., 2009, 94(14): 141912
[14] Ramzan M, Ahuja R. Ab ignition molecular dynamics study of the hydrogen deuterium exchange in bulk lithiumborohydride (LiBH_4). Appl. Phys. Lett., 2009, 94(14): 141903
[15] Allis D G, Hudson B S. Inelastic neutron scattering spectra of NaBH_4 and KBH_4: reproduction of anion mode shifts via periodic DFT. Chem. Phys. Lett., 2004, 385(3-4): 166-172
[16] Frankcombe T J, Kroes G J, Züttel A. Theoretical calculation of the energy of formation of LiBH_4. Chem. Phys. Lett., 2005, 405(1-3): 73-78
[17] Talyzin A V, Andersson O, Sundqvist B, et al. High-pressure phase transition in LiBH4. J. Solid State Chem., 2007, 180(2): 510-517
[18] Kumar R S, Kim E, Tschauner O, et al. Pressure-induced structural phase transition in NaAlH_4. Phys. Rev. B, 2007, 75(17): 174110
[19] Kumar R S, Cornelius A L. Structural phase transitions in RbBH_4 under compression. J. Alloys Compd., 2009, 476(1-2): 5-8
[20] Talyzin A V, Sundqvist B. Reversible phase transition in LiAlH_4 under high pressure conditions. Phys. Rev. B, 2004, 70(18): 180101(R)
[21] Pitt P M, Blanchard D, Hauback B C, et al. Pressure-induced phase transitions of the LiAlD4 system. Phys. Rev. B, 2005, 72(21): 214113
[22] Talyzin A V, Sundqvist B. High-pressure study of NaAlH_4 by Raman spectroscopy up to 17 GPa. High Press. Res., 2006, 26(3): 165-173
[23] Lodziana Z, Vegge T. Structural stability of complex hydrides: LiBH_4 revisited. Phys. Rev. Lett., 2004, 93(14): 145501
[24] Renaudin G, Gomes S, Hagemann H, et al. Structural and spectroscopic studies on the alkali borohydrides MBH4 (M=Na, K, Rb, Cs). J. Alloys Compd., 2004, 375(1-2): 98-106
[25] Ravindran P, Vajeeston P, Fjellv?g H, et al. Chemical-bonding and high-pressure studies on hydrogen-storage material. Comput. Mater. Sci., 2004, 30(3-4): 349-357
[26] Vajeeston P, Ravindran P, Kjekshus A, et al. Structural stability of alkali boron tetrahydrides ABH_4 (A=Li, Na, K, Rb, Cs) from first principle calculation. J. Alloys Compd., 2005, 387(1-2): 97-104
[27] Abrahams S C, Kalnajs J. The lattice constants of the alkali borohydrides and the low-temperature phase of sodium borohydride. J. Chem. Phys., 1954, 22(3): 434-436
[28] Kumar R S, Cornelius A L. Structural transition in NaBH4 under pressure. Appl. Phys. Lett., 2005, 87(26): 261916
[29] Johnston L, Hallett N C. Low temperature heat capacities of inorganic solids. XIV. Heat capacity of sodium borohydride from 15-300oK. J. Am. Chem. Soc., 1953, 75(6): 1467-1468
[30] Sundqvist B, Andersson O. Low-temperature phase transformation in NaBH_4 under pressure. Phys. Rev. B, 2006, 73(9): 092102
[31] Araújo C M, Ahuja R, Talyzin A V, et al. Pressure-induced structural phase transition in NaBH_4. Phys. Rev. B, 2005, 72(5): 054125
[32] Kim E, Kumar R, Weck P F, et al. Pressure-driven phase transitions in NaBH4: theory and experiments. J. Phys. Chem. B, 2007, 111(50): 13873-13876
[33] Filinchuk Y, Talyzin A V, Chernyshov D, et al. High-pressure phase of NaBH4: crystal structure from synchrotron powder diffraction data. Phys. Rev. B, 2007, 76(9): 092104
[34]王中林,康振川.功能与智能材料结构演化与结构分析.北京:科学出版社, 2002, 352-354
[35] Arnaud B, Alouani M. Electron-hole excitations in Mg2Si and Mg2Ge compounds. Phys. Rev. B, 2001, 64(3): 033202
[36] Nikitin E N, Bazanov V G, Tarasov V I. Thermoelectric properties of Mg_2Si-Mg_2Sn solid solution. Sov. Phys. Solid State, 1962, 3(10): 2648-2652
[37] Noda Y, Kon H, Furukawa Y, et al. Preparation and Thermoelectric Properties of Mg_2Si1-xGex (x=0.0～0.4) Solid Solution Semiconductors. Mater. Trans. JIM, 1992, 33(9): 845-850
[38] Noda Y, Kon H, Furukawa Y, et al. Temperature Dependence of Thermoelectric Properties of Mg2Si0.6Ge0.4. Mater. Trans. JIM, 1992, 33(9): 851-855
[39] Tani J, Kido H. Thermoelectric properties of Bi-doped Mg2Si semiconductors. Physica. B, 2005, 364(1-4): 218-224
[40] Li G H, Gill H S, Varin R A. Magnesium silicide intermetallic alloys. Metall. Trans. A, 1993, 24(11): 2383-2391
[41] Chen C Y, Tsao C Y A. Spray forming of silicon added AZ91 magnesium alloy and its workability. Mater. Sci. Eng. A, 2004, 383(1): 21-29
[42] Vantomme A, Mahan J E, Langouche G, et al. Thin film growth of semiconducting Mg_2Si by codeposition. Appl. Phys. Lett., 1997, 70(9): 1086-1088
[43] Janot R, Cuevas F, Latroche M, et al. Influence of crystallinity on the structural and hydrogenation properties of Mg_2X phases (X=Ni, Si, Ge, Sn). Intermetallics, 2006, 14(2): 163-169
[44] Prigent J, Gupta M. Ab initio study of the hydrogenation properties of Mg-based binary and ternary compounds Mg_2X (X=Ni, Si) and YMgNi_4. J. Alloys Compd., 2007, 446-447(31): 90-95
[45] Corkill J L, Cohen M L. Structural, bonding, and electronic properties of IIA-IV antifluorite compounds. Phys. Rev. B, 1993, 48(23): 17138-17144
[46] Arnaud B, Alouani M. Electron-hole excitations in Mg2Si and Mg2Ge compounds. Phys. Rev. B, 2001, 64(3): 033202
[47] Tani J I, Kido H. Lattice dynamics of Mg2Si and Mg2Ge compounds from first-principles calculations. Comput. Mater. Sci., 2008, 42(3): 531-536
[48] Laref S, Laref A. Mechanical, electronic and optical properties of antifluorites semiconductors X_2C (X=Mg, Be). Comput. Mater. Sci., 2008, 44(2): 664-669
[49] Saravanan R, Robert M C. Local structure of the thermoelectric material Mg_2Si using XRD. J. Alloys Compd., 2009, 479(1-2): 26-31
[50] Takagi N, Sato Y, Matsuyama T, et al. Growth and structural properties of Mg_2Si and Ca2Si bulk crystals. Appl. Surf. Sci., 2005, 244(1-4): 330-333
[51] Benhelal O, Chahed A, Laksari S, et al. First-principles calculations of the structural, electronic and optical properties of IIA-IV antifluorite compounds. Phys. Stat. Sol. (b), 2005, 242(10): 2022-2032
[52] Anastassakis E, Hawranek J P. Elastic constants of II-IV semiconductors. Phys. Rev. B, 1972, 5(10): 4003-4007
[53] Clark C R, Wright C, Suryanarayana C, et al. Synthesis of Mg_2X (X= Si, Ge, or Sn) intermetallics by mechanical alloying. Materials Letters, 1997, 33(1-2): 71-75
[54] Janot R, Cuevas F, Latroche M, et al. Influence of crystallinity on the structural and hydrogenation properties of Mg_2X phases (X=Ni, Si, Ge, Sn). Intermetallics, 2006, 14(2): 163-169
[55] Tani J I, Kido H. Thermoelectric properties of Sb-doped Mg2Si semiconductors. Intermetallics, 2007, 15(9): 1202-1207
[56] Song R, Yazheng L, Tatsuhiko A. Solid state synthesis and thermoelectric properties of Mg-Si-Ge system. J. Mat. Sci. Technol., 2005, 21(5): 618-622
[57] Guo E J, Ma B X, Wang L P. Modification of Mg2Si morphology in Mg-Si alloys with Bi. J. Mat. Proc. Technol., 2008, 206(1-3): 161-166
[58] Zhang J, Fan Z, Wang Y Q, et al. Microstructural development of Al-15wt.% Mg_2Si in situ composite with mischmetal addition. Mater. Sci. Eng. A, 2000, 281(1-2): 104-112
[59] Wang L P, Guo E J, Ma B X. Modification effect of lanthanum on primary phase Mg_2Si in Mg-Si alloys. J. Rare Earths, 2008, 26(1): 105-109
[60] Cannon P, Conlin E T. Magnesium compounds: new dense phases. Scinence, 1964, 145(3631): 487-489
[61] Range K J, Grosch G H, Andratschke M. Studies on AB2-type intermetallic compounds. Part V1. The crystal structure of Mg_9Sn_5, a supposed high-pressure modification of Mg2Sn. J. Alloys Compd., 1996, 244(1-2): 170-174
[62] Bolotina N B, Dyuzheva T I, Bendeliani N A, et al. Growth of crystals, composite crystal structures and electrical resistance of high-pressure phases of Mg_2B_(1+X )(B=Sn, Ge). J. Alloy. Compd., 1998, 278(1-2): 29-33
[63] Hao J, Zou B, Zhu P, et al. In situ X-ray observation of phase transitions in Mg2Si under high pressure. Solid State Commun., 2009, 149(17-18): 689-692
[64] Kalarasse F, Bennecer B. Electronic and optical properties of the antifluorite semiconductors Be_2C and Mg_2X (X= C, Si, Ge) under hydrostatic pressure. J. Phys. Chem. Solids, 2008, 69(7): 1775-1781
[65] Schon J C, Cancareic Z, Jansen M. Structure prediction of high-pressure phases for alkali metal sulfides. J. Chem. Phys., 2004, 121(5): 2289
[66] Kunc K, Loa I, Grzechnik A, et al. Li2O at high pressures: structural properties, phase-transition, and phonons. Phys. Stat. Sol. (b), 2005, 242(9): 1857-1863
[67] Lazicki A, Yoo C S, Evans W J, et al. Pressure-induced antifluorite-to-anticotunnite phase transition in lithium oxide. Phys. Rev. B, 2006, 73(18): 184120
[68] Kunc K, Loa I, Syassen K. High-pressure phases of Lithia Li2O: first-principles calculations. Phys. Rev. B, 2008, 77(9): 094110
[69] Manjón F J, Errandonea D. Pressure-induced structural phase transitions in materials and earth sciences. Phys. Stat. Sol. (b), 2009, 246(1): 9-31
[70] Züttel A. Hydrogen storage methods. Naturwissenschaften, 2004, 91(4): 157-172
[71] Sakintuna B, Lamari-Darkrim F, Hirscher M. Metal hydride materials for solid hydrogen storage: a review. Int. J. Hydrogen Energy, 2007, 32(9): 1121-1140
[72] Klyamkin S N. Metal hydride compositions on the basis of magnesium as materials for hydrogen accumulation. Russ. J. Gen. Chem., 2007, 77(4): 712-720
[73] Carbonneau Y, Couture A, Van Neste A, et al. Thermoelectric properties of Ca-Mg-Si alloys. Mater. Trans., 2009, 50(7): 1725-1729
[74] Kim J M, Seong K D, Jun J H, et al. Microstructural characteristics and mechanical properties of Al-2.5wt.% Li-1.2 wt.% Cu-xMg alloys. J. Alloys Compd., 2007, 434-435(31): 324-326
[75] Park S S, Bae G T, Kang D H, et al. Microstructure and tensile properties of twin-roll cast Mg-Zn-Mn-Al alloys. Scr. Mater., 2007, 57(9): 793-796
[76] Axel H, Eisenmann B, Sch?fer H, et al. Zur kenntnis von CaMgSi, CaMgGe und CaMgSn. Z. Naturforsch, 1969, 24b(3): 815-817
[77] Nesper R, Currao A, Wengert S. Nonaromatic planar Si_(12) ring system of approximate D6h symmetry in Ca7Mg1.5+δSi14。Chem. Eur. J., 1998, 4(11): 2251-2257
[78] Grobner J, Chumak I, Schmid-Fetzer R. Experimental study of ternary Ca-Mg-Si phase equilibria and thermodynamic assessment of Ca-Si and Ca-Mg-Si systems. Intermetallics, 2003, 11(10): 1065-1074
[79] Zmiy O F, Gladyshevskii E I. X-ray investigation of the system Ca-Mg-Si in region 0-33, 3 at.% Ca. Visn. Lviv. Derz. Univ. Se Khim., 1969, 11(1): 38-39
[80] Ben-Hamu G, Eliezer D, Shin K S. The role of Si and Ca on new wrought Mg-Zn-Mn based alloy. Mater. Sci. Eng. A, 2007, 447(1-2): 35-43
[81] Kim J J, Kim D H, Shin K S, et al. Modification of Mg2Si morphology in squeeze cast Mg-Al-Zn-Si alloys by Ca or P addition. Scr. Mater., 1999, 41(3): 333-340
[82] Ai Y, Luo C P, Liu J. Twinning of CaMgSi phase in a cast Mg-1.0Ca-0.5Si-0.3Zr alloy. Acta Mater., 2007, 55(2): 531-538
[83] Hosono T, Kuramoto M, Matsuzawa Y, et al. Formation of CaMgSi at Ca_2Si/Mg2_Si interface. Appl. Surf. Sci., 2003, 216(1-4): 620-624
[84] Niwa Y, Todaka Y, Masuda T, et al. On the observation of a new ternary MgSiCa phase in Mg-Si alloys. Mater. Trans. A, 1998, 29(6): 1759-1763
[85] Whalen J B, Zaikina J V, Achey R, et al. Metal to semimetal transition in CaMgSi crystals grown from Mg-Al flux. Chem. Mater., 2010, 22(5): 1846-1853
[86] Cabrera C R, Abru?a H D. Synthesis and photoelectrochemistry of polycrystalline thin films of p-WSe2, p-WS2, and p-MoSe_2. J. Electrochem. Soc., 1988, 135(6): 1436-1442
[87] Rapoport L, Lvovsky M, Lapsker I, et al. Slow release of fullerene-like WS_2 nanoparticles from Fe-Ni graphite matrix: a self-lubricating nanocomposite. Nano Lett., 2001, 1(3): 137-140
[88] Santiago-Ortiz Y, Torres G I, Díaz A, et al. Surface analysis and photoelectrochemical studies of mixed polycrystals of p-WSe_2/WS_2. J. Electrochem. Soc., 1995, 142(8): 2770-2776
[89] Scrosati B. Challenge of portable power. Nature, 1995, 373(6515): 557-557
[90] Armstrong A R, Bruce P G. Synthesis of layered LiMnO2 as an electrode for rechargeable lithium batteries. Nature, 1996, 381(6582): 499-500
[91] Chen J, Li S L, Tao Z L, et al. Titanium disulfide nanotubes as hydrogen-storage materials. J. Am. Chem. Soc., 2003, 125(18): 5284-5285
[92] Riekel C, Sch?llhorn R. Structure refinement of nonstoichiometric TiS_2. Mater. Res. Bull., 1975, 10(7): 629-633
[93] Greenaway D L, Nitsche R. Preparation and optical properties of group IV-VI2 chalcogenides having the CdI_2 structure. J. Phys. Chem. Solids, 1965, 26(9): 1445-1458
[94] Liang W Y, Lucovsky G, White R M, et al. Optical and electrical studies of Ti- and Ta-dichalcogenides: plasmons. Philos. Mag., 1976, 33(3): 493-503
[95] Klipstein P C, Friend R H. Semiconductor to semimetal transition in TiS_2 at 40 kbar. J. Phys. C, 1984, 17(15): 2713-2734
[96] Bocharov S, Drager G, Heumann D, et al. Polarized x-ray-absorption spectra of TiS_2, TiSe_2, and TiTe_2. Phys. Rev. B, 1998, 58(12): 7668-7674
[97] Fang C M, De Groot R A, Haas C. Bulk and surface electronic structure of 1T-TiS_2 and 1T-TiSe_2. Phys. Rev. B, 1997, 56(8): 4455-4463
[98] Wu Z Y, Ouvrard G, Lemaux S, et al. Sulfur K-edge x-ray-absorption study of the charge transfer upon lithium intercalation into titanium disulfide. Phys. Rev. Lett., 1996, 77(10): 2101-2104
[99] Wu Z Y, Ouvrard G, Moreau P, et al. Interpretation of preedge features in the Ti and S K-edge x-ray-absorption near-edge spectrain the layered disulfides TiS_2 and TaS_2. Phys. Rev. B, 1997, 55(15): 9508-9513
[100] Allan D R, Kelsey A A, Clark S J, et al. High-pressure semiconductor-semimetal transition in TiS_2. Phys. Rev. B, 1998, 57(9): 5106-5110
[101] Sharma S, Nautiyal T, Singh G S, et al. Electronic structure of 1T-TiS_2. Phys. Rev. B, 1999, 59(23): 14833-14836
[102] Aksoy R, Selvi E, Knudson R, et al. A high pressure x-ray diffraction study of titanium disulfide. J. Phys.: Condens. Matter, 2009, 21(2): 025403
[103] Batsanova L R, Yur’ev G S, Doronina V P. The structure of vitreous beryllium fluoride. J. Struct. Chem., 1968, 9(1): 63-68
[104] Narten A H. Diffraction pattern and structure of noncrystalline BeF2 and SiO_2 at 25 oC. J. Chem. Phys., 1972, 56(5): 1905-1909
[105] Vaslow F, Narten A H. Diffraction pattern and structure of molten BeF_2-LiF solutions. J. Chem. Phys., 1973, 59(9): 4949-4954
[106] Leadberter A J, Wright A C. Diffraction studies of glass structure IV. The structure of vitreous BeF_2 by X-ray and neutron diffraction. J. Non-Cryst. Solids, 1972, 7(2): 156-167
[107] Hargittai M. Molecular structure of metal halides. Chem. Rev., 2000, 100(6): 2233-2302
[108] Delgado O F, Dress W M A, Huson D H, et al. Systematic enumeration of crystalline networks. Nature, 1999, 400(6745): 644-646
[109] Foster M D, Simperler A S, Bell R G, et al. Chemically feasible hypothetical crystalline networks. Nat. Mater., 2004, 3(4): 234-238
[110] Zwjinenburg M A, Cora F, Bell R G. Isomorphism of anhydrous tetrahedral halides and silicon chalcogenides: energy landscape of crystalline BeF_2, BeCl_2, SiO_2, and SiS_2. J. Am. Chem. Soc., 2008, 130(33): 11082-11087
[111] Everest D A. The chemistry of beryllium. Amsterdam: Elsevier, 1964, 208-223
[112] Wright A F, Fitch A N, Wright A C. The preparation and structure of theα- andβ-Quartz polymorphs of beryllium fluoride. J. Sol. Stat. Chem., 1988, 73(2):298-304
[113] Ghalsasi P G, Ghalsasi P S. Single crystal X-ray structure of BeF_2:α-Quartz. Inorg. Chem., 2011, 50(1): 86-89
[114] Andrault D, Fiquet G, Guyot F, et al. Pressure-induced landau-type transition in stishovite. Science, 1998, 282(5389): 720-724
[115] Kingma K J, Cohen R E, Hemley R J, et al. Transformation of stishovite to a denser phase at lower-mantle pressures. Nature, 1995, 374(6519): 243-245
[116] Dubrovinsky L S, Saxena S K, Lazor P, et al. Experimental and theoretical identification of a new high-pressure phase of silica. Nature, 1997, 388(6640): 362-364
[117] Haines J, Léger J M, Gorelli F, et al. Crystalline post-quartz phase in silica at high pressure. Phys. Rev. Lett., 2001, 87(15): 155503
[118]唐敖庆.量子化学.北京:科学出版社, 1982, 211-212
[119] Born M, Huang K. Dynamical Theory of Crystal Lattice. Oxford: Oxford University press, 1954, 6-58
[120]徐光宪,黎乐民,王德民.量子化学中册.北京:科学出版社, 2001, 134-156
[121] Hohenberg P H, Kohn W. Inhomogeneous electron gas. Phys. Rev., 1964, 136(3B): B864-B871
[122] Kohn W, Sham L J. Self-consistent equations including exchange and correlation effects. Phys. Rev., 1965, 140(4A): A1133-A1138
[123] Ceperley D M, Alder B J. Ground state of the electron gas by a stochastic method. Phys. Rev. Lett., 1980(7), 45: 566-569
[124] Perdew J P. Accurate density functional for the energy: real-space cutoff of the gradient expansion for the exchange hole. Phys. Rev. Lett., 1985, 55(16): 1665-1668
[125] Perdew J P, Zunger A. Self-interaction correction to density-functional approximations for many-electron system. Phys. Rev. B, 1981, 23(10): 5048-5079
[126] Perdew J P, Chevary J A, Vosko S H, et al. Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation. Phys. Rev. B, 1992, 46(11): 6671-6687
[127] Perdew J P, Burke K, Ernzerhof M. Generalized gradient approximation made simple. Phys. Rev. Lett., 1996, 77(18): 3865-3868
[128] Hammer B, Hansen L B, Norskov J K. Improved adsorption energetics within density-functional theory using revised Perdew-Burke-Ernzerhof functionals. Phys. Rev. B, 1999, 59(11): 7413-7421
[129] Wu Z, Cohen R E. More accurate generalized gradient approximation for solids. Phys. Rev. B, 2006, 73(23): 235116
[130] Monkhorst H J, Pack J D. Special points for brillouin zone intergrations-a reply. Phys. Rev. B, 1977, 16(4): 1748-1749
[131] Phillips J C, Kleinman L. New method for calculating wave functions in crystals and molecules. Phys. Rev., 1959, 116(2): 287-294
[132] Antoncik E. Approximate formulation of the orthogonalized plane-wave method. J. Phys. Chem. Solids, 1959, 10(4): 314-320
[133] Hamann D R, Schluter M, Chiang C. Norm-conserving pseudopotentials. Phys. Rev. Lett., 1979, 43(20): 1494-1497
[134] Vanderbilt D. Soft self-xonsistent pseudopotentials in generalized eigenvalue formalism. Phys. Rev. B, 1990, 41(11): 7892-7895
[135] Car R, Parrinello M. Unified approach for molecular dynamics and density-functional theory. Phys. Rev. Lett., 1985, 55(22): 2471-2474
[136]张其土.无机材料科学基础.上海:华东理工大学出版社, 2007, 11-36
[137] Kirkpatrick S, Gelatt C D, Vecchi M P, et al. Optimization by simulated annealing. Science, 1983, 220(4598): 671-680
[138] Wang Y C, Lv J, Zhu L, et al. Crystal structure prediction via particle-swarm optimization. Phys. Rev. B, 2010, 82(9): 094116
[139] Wales D, Doye J. Global optimization by basin-hopping and the lowest energy structures of Lennard-Jones clusters containing up to 110 atoms. J. Phys. Chem. A, 1997, 101(28): 5111-5116
[140] Martoňák R, Laio A, Parrinello M. Predicting crystal structures: the Parrinello-Rahman method revisited. Phys. Rev. Lett., 2003, 90(7): 075503
[141] Mujica A, Needs R J. Theoretical study of the high-pressure phase stability of GaP, InP, and InAs. Phys. Rev. B, 1997, 55(15): 9659-9670
[142] Pickard C J, Needs R J. Structures at high pressure from random searching. Phys. Status solidi B, 2009, 246(3): 536-540
[143] Segall M D, Lindan P L D, Probert M J, et al. First-principles simulation: ideas, illustrations and the CASTEP code. J. Phys.: Condens. Matter, 2002, 14(11): 2717-2744
[144] Payne M C, Teter M P, Allen D C, et al. Iterative minimization techniques for ab initio total-energy calculations: molecular dynamics and conjugate gradients. Rev. Mod. Phys., 1992, 64(4): 1045-1097
[145] Milman V, Winkler B, White J A, et al. Electronic structure, properties, and phase stability of inorganic crystals: a pseudopotential plane-wave study. Int. J. Quantum Chem., 2000, 77(5): 895-910
[146] Kalpana G, Palanivel B, Rajagopalan M. Electronic structure and structural phase stability in BaS, BaSe, and BaTe. Phys. Rev. B, 1994, 50(17): 12318-12325
[147] Wu X, Dong Y H, Qin S, et al. First-principles study of the pressure-induced phase transition in CaTiO3. Solid State Commun., 2005, 136(7): 416-420
[148] Birch F. Finite strain isotherm and velocities for single-crystal and polycrystalline NaCl at high pressures and 300o K. J. Geophys. Res., 1978, 83(B3): 1257-1268
[149] Aronsson B, ?selius J. The crystal structure of Ru_2Si. Acta Chem. Scand., 1961, 15(1): 1571-1574
[150] Venturini G, Ijjaali I, Ressouche E, et al. Neutron diffraction study of the HoMnSi, LuMnSi and Sc_(0.9)Lu_(0.1)MnSi compounds. J. Alloys Compd., 1997, 256(1-2): 65-75
[151]沈学础.半导体光学性质.北京:科学出版社, 1992: 7-10
[152] Bisi O, Braicovich L, Carbone C, et al. Chemical bond and electronic states in calcium silicides: theory and comparison with synchrotron-radiation photoemission. Phys. Rev. B, 1989, 40(15): 10194-10209
[153] Lebègue S, Arnaud B, Alouani M. Calculated quasiparticle and optical properties of orthorhombic and cubic Ca_2Si. Phys. Rev. B, 2005, 72(8): 085103
[154] Daisuke N H, Asa S, Ritsuko N, et al. The stability and equation of state for the cotunnite phase of TiO_2 up to 70 GPa. Phys. Chem. Minerals, 2010, 37(3): 129-136
[155] Luo W, Yang S F, Wang Z C, et al. Structural phase transitions in brookite-type TiO_2 under high pressure. Solid State Commun., 2005, 133(1): 49-53
[156] Sasaki T. Stability of rutile-type TiO2 under high pressure. J. Phys.: Condens. Matter., 2002, 14(44): 10557
[157] Kessler J R, Monberg E, Nicol M. Study of fluorite and related divalentfluoride systems at high pressure by Raman spectroscopy. J. Chem. Phys., 1974, 60(12): 5057-5065
[158] Kourouklis G A, Anastassakis E. Pressure-induced Phase transition in SrF_2: a Raman study. Phys. Rev. B, 1986, 34(2): 1233-1237
[159] Léger J M, Haines J, Danneels C. Phase transition sequence induced by high-pressure in CaCl_2. J. Phys. Chem. Solids, 1998, 59(8): 1199-1204
[160] Bedford K L. Ab initio cluster calculations of the electronic structure of crystalline BeF_2. Solid State communications, 1983, 45(6): 487-490
[2]周馨我.功能材料学.北京:北京理工大学出版社, 2009, 1-2
[3]贡长生,张克立.新型功能材料.北京:化学工业出版社, 2001, 1-6
[4] Trimarchi G, Zunger A. Global space-group optimization problem: finding the stablest crystal structure without constraints. Phys. Rev. B, 2007, 75(10): 104113
[5] Ogitsu T. Computational physics: a quantum puzzle revisited. Nature Phys., 2007, 3(7): 452-453
[6] Pickard C J, Needs R J. Structure of Phase III of solid hydrogen. Nature Phys., 2007, 3(7): 473-476
[7] Oganov A R, Glass C W. Evolutionary crystal structure prediction as a tool in material design. J. Phys.: Condens. Matter, 2008, 20(6): 064210
[8] Behler J, Martoňák R, Donadio D, et al. Metadynamics simulations of the high-pressure phases of silicon employing a high-dimensional neural network potential. Phys. Rev. Lett., 2008, 100(18):185501
[9] McMillan P F. New materials from high-pressure experiments. Nature Mater., 2002, 1(1): 19-25
[10] Gregoryanz E, Sanloup C, Somayazulu M, et al. Synthesis and characterization of a binary noble metal nitride. Nature Mater., 2004, 3(5): 294-297
[11] Horvath-Bordon E, Riedel R, Zerr A, et al. High-pressure chemistry of nitride-based materials. Chem. Soc. Rev., 2006, 35(10): 987-1014
[12] He J L, Guo L C, Guo X J, et al. Predicting hardness of dense C3N4 polymorphs. Appl. Phys. Lett., 2006, 88(10): 101906
[13] Oguchi H, Matsuo M, Hummelsh?J J S, et al. Experimental and computational studies on structural transitions in the LiBH4-Lil pseudobinary system. Appl. Phys. Lett., 2009, 94(14): 141912
[14] Ramzan M, Ahuja R. Ab ignition molecular dynamics study of the hydrogen deuterium exchange in bulk lithiumborohydride (LiBH_4). Appl. Phys. Lett., 2009, 94(14): 141903
[15] Allis D G, Hudson B S. Inelastic neutron scattering spectra of NaBH_4 and KBH_4: reproduction of anion mode shifts via periodic DFT. Chem. Phys. Lett., 2004, 385(3-4): 166-172
[16] Frankcombe T J, Kroes G J, Züttel A. Theoretical calculation of the energy of formation of LiBH_4. Chem. Phys. Lett., 2005, 405(1-3): 73-78
[17] Talyzin A V, Andersson O, Sundqvist B, et al. High-pressure phase transition in LiBH4. J. Solid State Chem., 2007, 180(2): 510-517
[18] Kumar R S, Kim E, Tschauner O, et al. Pressure-induced structural phase transition in NaAlH_4. Phys. Rev. B, 2007, 75(17): 174110
[19] Kumar R S, Cornelius A L. Structural phase transitions in RbBH_4 under compression. J. Alloys Compd., 2009, 476(1-2): 5-8
[20] Talyzin A V, Sundqvist B. Reversible phase transition in LiAlH_4 under high pressure conditions. Phys. Rev. B, 2004, 70(18): 180101(R)
[21] Pitt P M, Blanchard D, Hauback B C, et al. Pressure-induced phase transitions of the LiAlD4 system. Phys. Rev. B, 2005, 72(21): 214113
[22] Talyzin A V, Sundqvist B. High-pressure study of NaAlH_4 by Raman spectroscopy up to 17 GPa. High Press. Res., 2006, 26(3): 165-173
[23] Lodziana Z, Vegge T. Structural stability of complex hydrides: LiBH_4 revisited. Phys. Rev. Lett., 2004, 93(14): 145501
[24] Renaudin G, Gomes S, Hagemann H, et al. Structural and spectroscopic studies on the alkali borohydrides MBH4 (M=Na, K, Rb, Cs). J. Alloys Compd., 2004, 375(1-2): 98-106
[25] Ravindran P, Vajeeston P, Fjellv?g H, et al. Chemical-bonding and high-pressure studies on hydrogen-storage material. Comput. Mater. Sci., 2004, 30(3-4): 349-357
[26] Vajeeston P, Ravindran P, Kjekshus A, et al. Structural stability of alkali boron tetrahydrides ABH_4 (A=Li, Na, K, Rb, Cs) from first principle calculation. J. Alloys Compd., 2005, 387(1-2): 97-104
[27] Abrahams S C, Kalnajs J. The lattice constants of the alkali borohydrides and the low-temperature phase of sodium borohydride. J. Chem. Phys., 1954, 22(3): 434-436
[28] Kumar R S, Cornelius A L. Structural transition in NaBH4 under pressure. Appl. Phys. Lett., 2005, 87(26): 261916
[29] Johnston L, Hallett N C. Low temperature heat capacities of inorganic solids. XIV. Heat capacity of sodium borohydride from 15-300oK. J. Am. Chem. Soc., 1953, 75(6): 1467-1468
[30] Sundqvist B, Andersson O. Low-temperature phase transformation in NaBH_4 under pressure. Phys. Rev. B, 2006, 73(9): 092102
[31] Araújo C M, Ahuja R, Talyzin A V, et al. Pressure-induced structural phase transition in NaBH_4. Phys. Rev. B, 2005, 72(5): 054125
[32] Kim E, Kumar R, Weck P F, et al. Pressure-driven phase transitions in NaBH4: theory and experiments. J. Phys. Chem. B, 2007, 111(50): 13873-13876
[33] Filinchuk Y, Talyzin A V, Chernyshov D, et al. High-pressure phase of NaBH4: crystal structure from synchrotron powder diffraction data. Phys. Rev. B, 2007, 76(9): 092104
[34]王中林,康振川.功能与智能材料结构演化与结构分析.北京:科学出版社, 2002, 352-354
[35] Arnaud B, Alouani M. Electron-hole excitations in Mg2Si and Mg2Ge compounds. Phys. Rev. B, 2001, 64(3): 033202
[36] Nikitin E N, Bazanov V G, Tarasov V I. Thermoelectric properties of Mg_2Si-Mg_2Sn solid solution. Sov. Phys. Solid State, 1962, 3(10): 2648-2652
[37] Noda Y, Kon H, Furukawa Y, et al. Preparation and Thermoelectric Properties of Mg_2Si1-xGex (x=0.0～0.4) Solid Solution Semiconductors. Mater. Trans. JIM, 1992, 33(9): 845-850
[38] Noda Y, Kon H, Furukawa Y, et al. Temperature Dependence of Thermoelectric Properties of Mg2Si0.6Ge0.4. Mater. Trans. JIM, 1992, 33(9): 851-855
[39] Tani J, Kido H. Thermoelectric properties of Bi-doped Mg2Si semiconductors. Physica. B, 2005, 364(1-4): 218-224
[40] Li G H, Gill H S, Varin R A. Magnesium silicide intermetallic alloys. Metall. Trans. A, 1993, 24(11): 2383-2391
[41] Chen C Y, Tsao C Y A. Spray forming of silicon added AZ91 magnesium alloy and its workability. Mater. Sci. Eng. A, 2004, 383(1): 21-29
[42] Vantomme A, Mahan J E, Langouche G, et al. Thin film growth of semiconducting Mg_2Si by codeposition. Appl. Phys. Lett., 1997, 70(9): 1086-1088
[43] Janot R, Cuevas F, Latroche M, et al. Influence of crystallinity on the structural and hydrogenation properties of Mg_2X phases (X=Ni, Si, Ge, Sn). Intermetallics, 2006, 14(2): 163-169
[44] Prigent J, Gupta M. Ab initio study of the hydrogenation properties of Mg-based binary and ternary compounds Mg_2X (X=Ni, Si) and YMgNi_4. J. Alloys Compd., 2007, 446-447(31): 90-95
[45] Corkill J L, Cohen M L. Structural, bonding, and electronic properties of IIA-IV antifluorite compounds. Phys. Rev. B, 1993, 48(23): 17138-17144
[46] Arnaud B, Alouani M. Electron-hole excitations in Mg2Si and Mg2Ge compounds. Phys. Rev. B, 2001, 64(3): 033202
[47] Tani J I, Kido H. Lattice dynamics of Mg2Si and Mg2Ge compounds from first-principles calculations. Comput. Mater. Sci., 2008, 42(3): 531-536
[48] Laref S, Laref A. Mechanical, electronic and optical properties of antifluorites semiconductors X_2C (X=Mg, Be). Comput. Mater. Sci., 2008, 44(2): 664-669
[49] Saravanan R, Robert M C. Local structure of the thermoelectric material Mg_2Si using XRD. J. Alloys Compd., 2009, 479(1-2): 26-31
[50] Takagi N, Sato Y, Matsuyama T, et al. Growth and structural properties of Mg_2Si and Ca2Si bulk crystals. Appl. Surf. Sci., 2005, 244(1-4): 330-333
[51] Benhelal O, Chahed A, Laksari S, et al. First-principles calculations of the structural, electronic and optical properties of IIA-IV antifluorite compounds. Phys. Stat. Sol. (b), 2005, 242(10): 2022-2032
[52] Anastassakis E, Hawranek J P. Elastic constants of II-IV semiconductors. Phys. Rev. B, 1972, 5(10): 4003-4007
[53] Clark C R, Wright C, Suryanarayana C, et al. Synthesis of Mg_2X (X= Si, Ge, or Sn) intermetallics by mechanical alloying. Materials Letters, 1997, 33(1-2): 71-75
[54] Janot R, Cuevas F, Latroche M, et al. Influence of crystallinity on the structural and hydrogenation properties of Mg_2X phases (X=Ni, Si, Ge, Sn). Intermetallics, 2006, 14(2): 163-169
[55] Tani J I, Kido H. Thermoelectric properties of Sb-doped Mg2Si semiconductors. Intermetallics, 2007, 15(9): 1202-1207
[56] Song R, Yazheng L, Tatsuhiko A. Solid state synthesis and thermoelectric properties of Mg-Si-Ge system. J. Mat. Sci. Technol., 2005, 21(5): 618-622
[57] Guo E J, Ma B X, Wang L P. Modification of Mg2Si morphology in Mg-Si alloys with Bi. J. Mat. Proc. Technol., 2008, 206(1-3): 161-166
[58] Zhang J, Fan Z, Wang Y Q, et al. Microstructural development of Al-15wt.% Mg_2Si in situ composite with mischmetal addition. Mater. Sci. Eng. A, 2000, 281(1-2): 104-112
[59] Wang L P, Guo E J, Ma B X. Modification effect of lanthanum on primary phase Mg_2Si in Mg-Si alloys. J. Rare Earths, 2008, 26(1): 105-109
[60] Cannon P, Conlin E T. Magnesium compounds: new dense phases. Scinence, 1964, 145(3631): 487-489
[61] Range K J, Grosch G H, Andratschke M. Studies on AB2-type intermetallic compounds. Part V1. The crystal structure of Mg_9Sn_5, a supposed high-pressure modification of Mg2Sn. J. Alloys Compd., 1996, 244(1-2): 170-174
[62] Bolotina N B, Dyuzheva T I, Bendeliani N A, et al. Growth of crystals, composite crystal structures and electrical resistance of high-pressure phases of Mg_2B_(1+X )(B=Sn, Ge). J. Alloy. Compd., 1998, 278(1-2): 29-33
[63] Hao J, Zou B, Zhu P, et al. In situ X-ray observation of phase transitions in Mg2Si under high pressure. Solid State Commun., 2009, 149(17-18): 689-692
[64] Kalarasse F, Bennecer B. Electronic and optical properties of the antifluorite semiconductors Be_2C and Mg_2X (X= C, Si, Ge) under hydrostatic pressure. J. Phys. Chem. Solids, 2008, 69(7): 1775-1781
[65] Schon J C, Cancareic Z, Jansen M. Structure prediction of high-pressure phases for alkali metal sulfides. J. Chem. Phys., 2004, 121(5): 2289
[66] Kunc K, Loa I, Grzechnik A, et al. Li2O at high pressures: structural properties, phase-transition, and phonons. Phys. Stat. Sol. (b), 2005, 242(9): 1857-1863
[67] Lazicki A, Yoo C S, Evans W J, et al. Pressure-induced antifluorite-to-anticotunnite phase transition in lithium oxide. Phys. Rev. B, 2006, 73(18): 184120
[68] Kunc K, Loa I, Syassen K. High-pressure phases of Lithia Li2O: first-principles calculations. Phys. Rev. B, 2008, 77(9): 094110
[69] Manjón F J, Errandonea D. Pressure-induced structural phase transitions in materials and earth sciences. Phys. Stat. Sol. (b), 2009, 246(1): 9-31
[70] Züttel A. Hydrogen storage methods. Naturwissenschaften, 2004, 91(4): 157-172
[71] Sakintuna B, Lamari-Darkrim F, Hirscher M. Metal hydride materials for solid hydrogen storage: a review. Int. J. Hydrogen Energy, 2007, 32(9): 1121-1140
[72] Klyamkin S N. Metal hydride compositions on the basis of magnesium as materials for hydrogen accumulation. Russ. J. Gen. Chem., 2007, 77(4): 712-720
[73] Carbonneau Y, Couture A, Van Neste A, et al. Thermoelectric properties of Ca-Mg-Si alloys. Mater. Trans., 2009, 50(7): 1725-1729
[74] Kim J M, Seong K D, Jun J H, et al. Microstructural characteristics and mechanical properties of Al-2.5wt.% Li-1.2 wt.% Cu-xMg alloys. J. Alloys Compd., 2007, 434-435(31): 324-326
[75] Park S S, Bae G T, Kang D H, et al. Microstructure and tensile properties of twin-roll cast Mg-Zn-Mn-Al alloys. Scr. Mater., 2007, 57(9): 793-796
[76] Axel H, Eisenmann B, Sch?fer H, et al. Zur kenntnis von CaMgSi, CaMgGe und CaMgSn. Z. Naturforsch, 1969, 24b(3): 815-817
[77] Nesper R, Currao A, Wengert S. Nonaromatic planar Si_(12) ring system of approximate D6h symmetry in Ca7Mg1.5+δSi14。Chem. Eur. J., 1998, 4(11): 2251-2257
[78] Grobner J, Chumak I, Schmid-Fetzer R. Experimental study of ternary Ca-Mg-Si phase equilibria and thermodynamic assessment of Ca-Si and Ca-Mg-Si systems. Intermetallics, 2003, 11(10): 1065-1074
[79] Zmiy O F, Gladyshevskii E I. X-ray investigation of the system Ca-Mg-Si in region 0-33, 3 at.% Ca. Visn. Lviv. Derz. Univ. Se Khim., 1969, 11(1): 38-39
[80] Ben-Hamu G, Eliezer D, Shin K S. The role of Si and Ca on new wrought Mg-Zn-Mn based alloy. Mater. Sci. Eng. A, 2007, 447(1-2): 35-43
[81] Kim J J, Kim D H, Shin K S, et al. Modification of Mg2Si morphology in squeeze cast Mg-Al-Zn-Si alloys by Ca or P addition. Scr. Mater., 1999, 41(3): 333-340
[82] Ai Y, Luo C P, Liu J. Twinning of CaMgSi phase in a cast Mg-1.0Ca-0.5Si-0.3Zr alloy. Acta Mater., 2007, 55(2): 531-538
[83] Hosono T, Kuramoto M, Matsuzawa Y, et al. Formation of CaMgSi at Ca_2Si/Mg2_Si interface. Appl. Surf. Sci., 2003, 216(1-4): 620-624
[84] Niwa Y, Todaka Y, Masuda T, et al. On the observation of a new ternary MgSiCa phase in Mg-Si alloys. Mater. Trans. A, 1998, 29(6): 1759-1763
[85] Whalen J B, Zaikina J V, Achey R, et al. Metal to semimetal transition in CaMgSi crystals grown from Mg-Al flux. Chem. Mater., 2010, 22(5): 1846-1853
[86] Cabrera C R, Abru?a H D. Synthesis and photoelectrochemistry of polycrystalline thin films of p-WSe2, p-WS2, and p-MoSe_2. J. Electrochem. Soc., 1988, 135(6): 1436-1442
[87] Rapoport L, Lvovsky M, Lapsker I, et al. Slow release of fullerene-like WS_2 nanoparticles from Fe-Ni graphite matrix: a self-lubricating nanocomposite. Nano Lett., 2001, 1(3): 137-140
[88] Santiago-Ortiz Y, Torres G I, Díaz A, et al. Surface analysis and photoelectrochemical studies of mixed polycrystals of p-WSe_2/WS_2. J. Electrochem. Soc., 1995, 142(8): 2770-2776
[89] Scrosati B. Challenge of portable power. Nature, 1995, 373(6515): 557-557
[90] Armstrong A R, Bruce P G. Synthesis of layered LiMnO2 as an electrode for rechargeable lithium batteries. Nature, 1996, 381(6582): 499-500
[91] Chen J, Li S L, Tao Z L, et al. Titanium disulfide nanotubes as hydrogen-storage materials. J. Am. Chem. Soc., 2003, 125(18): 5284-5285
[92] Riekel C, Sch?llhorn R. Structure refinement of nonstoichiometric TiS_2. Mater. Res. Bull., 1975, 10(7): 629-633
[93] Greenaway D L, Nitsche R. Preparation and optical properties of group IV-VI2 chalcogenides having the CdI_2 structure. J. Phys. Chem. Solids, 1965, 26(9): 1445-1458
[94] Liang W Y, Lucovsky G, White R M, et al. Optical and electrical studies of Ti- and Ta-dichalcogenides: plasmons. Philos. Mag., 1976, 33(3): 493-503
[95] Klipstein P C, Friend R H. Semiconductor to semimetal transition in TiS_2 at 40 kbar. J. Phys. C, 1984, 17(15): 2713-2734
[96] Bocharov S, Drager G, Heumann D, et al. Polarized x-ray-absorption spectra of TiS_2, TiSe_2, and TiTe_2. Phys. Rev. B, 1998, 58(12): 7668-7674
[97] Fang C M, De Groot R A, Haas C. Bulk and surface electronic structure of 1T-TiS_2 and 1T-TiSe_2. Phys. Rev. B, 1997, 56(8): 4455-4463
[98] Wu Z Y, Ouvrard G, Lemaux S, et al. Sulfur K-edge x-ray-absorption study of the charge transfer upon lithium intercalation into titanium disulfide. Phys. Rev. Lett., 1996, 77(10): 2101-2104
[99] Wu Z Y, Ouvrard G, Moreau P, et al. Interpretation of preedge features in the Ti and S K-edge x-ray-absorption near-edge spectrain the layered disulfides TiS_2 and TaS_2. Phys. Rev. B, 1997, 55(15): 9508-9513
[100] Allan D R, Kelsey A A, Clark S J, et al. High-pressure semiconductor-semimetal transition in TiS_2. Phys. Rev. B, 1998, 57(9): 5106-5110
[101] Sharma S, Nautiyal T, Singh G S, et al. Electronic structure of 1T-TiS_2. Phys. Rev. B, 1999, 59(23): 14833-14836
[102] Aksoy R, Selvi E, Knudson R, et al. A high pressure x-ray diffraction study of titanium disulfide. J. Phys.: Condens. Matter, 2009, 21(2): 025403
[103] Batsanova L R, Yur’ev G S, Doronina V P. The structure of vitreous beryllium fluoride. J. Struct. Chem., 1968, 9(1): 63-68
[104] Narten A H. Diffraction pattern and structure of noncrystalline BeF2 and SiO_2 at 25 oC. J. Chem. Phys., 1972, 56(5): 1905-1909
[105] Vaslow F, Narten A H. Diffraction pattern and structure of molten BeF_2-LiF solutions. J. Chem. Phys., 1973, 59(9): 4949-4954
[106] Leadberter A J, Wright A C. Diffraction studies of glass structure IV. The structure of vitreous BeF_2 by X-ray and neutron diffraction. J. Non-Cryst. Solids, 1972, 7(2): 156-167
[107] Hargittai M. Molecular structure of metal halides. Chem. Rev., 2000, 100(6): 2233-2302
[108] Delgado O F, Dress W M A, Huson D H, et al. Systematic enumeration of crystalline networks. Nature, 1999, 400(6745): 644-646
[109] Foster M D, Simperler A S, Bell R G, et al. Chemically feasible hypothetical crystalline networks. Nat. Mater., 2004, 3(4): 234-238
[110] Zwjinenburg M A, Cora F, Bell R G. Isomorphism of anhydrous tetrahedral halides and silicon chalcogenides: energy landscape of crystalline BeF_2, BeCl_2, SiO_2, and SiS_2. J. Am. Chem. Soc., 2008, 130(33): 11082-11087
[111] Everest D A. The chemistry of beryllium. Amsterdam: Elsevier, 1964, 208-223
[112] Wright A F, Fitch A N, Wright A C. The preparation and structure of theα- andβ-Quartz polymorphs of beryllium fluoride. J. Sol. Stat. Chem., 1988, 73(2):298-304
[113] Ghalsasi P G, Ghalsasi P S. Single crystal X-ray structure of BeF_2:α-Quartz. Inorg. Chem., 2011, 50(1): 86-89
[114] Andrault D, Fiquet G, Guyot F, et al. Pressure-induced landau-type transition in stishovite. Science, 1998, 282(5389): 720-724
[115] Kingma K J, Cohen R E, Hemley R J, et al. Transformation of stishovite to a denser phase at lower-mantle pressures. Nature, 1995, 374(6519): 243-245
[116] Dubrovinsky L S, Saxena S K, Lazor P, et al. Experimental and theoretical identification of a new high-pressure phase of silica. Nature, 1997, 388(6640): 362-364
[117] Haines J, Léger J M, Gorelli F, et al. Crystalline post-quartz phase in silica at high pressure. Phys. Rev. Lett., 2001, 87(15): 155503
[118]唐敖庆.量子化学.北京:科学出版社, 1982, 211-212
[119] Born M, Huang K. Dynamical Theory of Crystal Lattice. Oxford: Oxford University press, 1954, 6-58
[120]徐光宪,黎乐民,王德民.量子化学中册.北京:科学出版社, 2001, 134-156
[121] Hohenberg P H, Kohn W. Inhomogeneous electron gas. Phys. Rev., 1964, 136(3B): B864-B871
[122] Kohn W, Sham L J. Self-consistent equations including exchange and correlation effects. Phys. Rev., 1965, 140(4A): A1133-A1138
[123] Ceperley D M, Alder B J. Ground state of the electron gas by a stochastic method. Phys. Rev. Lett., 1980(7), 45: 566-569
[124] Perdew J P. Accurate density functional for the energy: real-space cutoff of the gradient expansion for the exchange hole. Phys. Rev. Lett., 1985, 55(16): 1665-1668
[125] Perdew J P, Zunger A. Self-interaction correction to density-functional approximations for many-electron system. Phys. Rev. B, 1981, 23(10): 5048-5079
[126] Perdew J P, Chevary J A, Vosko S H, et al. Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation. Phys. Rev. B, 1992, 46(11): 6671-6687
[127] Perdew J P, Burke K, Ernzerhof M. Generalized gradient approximation made simple. Phys. Rev. Lett., 1996, 77(18): 3865-3868
[128] Hammer B, Hansen L B, Norskov J K. Improved adsorption energetics within density-functional theory using revised Perdew-Burke-Ernzerhof functionals. Phys. Rev. B, 1999, 59(11): 7413-7421
[129] Wu Z, Cohen R E. More accurate generalized gradient approximation for solids. Phys. Rev. B, 2006, 73(23): 235116
[130] Monkhorst H J, Pack J D. Special points for brillouin zone intergrations-a reply. Phys. Rev. B, 1977, 16(4): 1748-1749
[131] Phillips J C, Kleinman L. New method for calculating wave functions in crystals and molecules. Phys. Rev., 1959, 116(2): 287-294
[132] Antoncik E. Approximate formulation of the orthogonalized plane-wave method. J. Phys. Chem. Solids, 1959, 10(4): 314-320
[133] Hamann D R, Schluter M, Chiang C. Norm-conserving pseudopotentials. Phys. Rev. Lett., 1979, 43(20): 1494-1497
[134] Vanderbilt D. Soft self-xonsistent pseudopotentials in generalized eigenvalue formalism. Phys. Rev. B, 1990, 41(11): 7892-7895
[135] Car R, Parrinello M. Unified approach for molecular dynamics and density-functional theory. Phys. Rev. Lett., 1985, 55(22): 2471-2474
[136]张其土.无机材料科学基础.上海:华东理工大学出版社, 2007, 11-36
[137] Kirkpatrick S, Gelatt C D, Vecchi M P, et al. Optimization by simulated annealing. Science, 1983, 220(4598): 671-680
[138] Wang Y C, Lv J, Zhu L, et al. Crystal structure prediction via particle-swarm optimization. Phys. Rev. B, 2010, 82(9): 094116
[139] Wales D, Doye J. Global optimization by basin-hopping and the lowest energy structures of Lennard-Jones clusters containing up to 110 atoms. J. Phys. Chem. A, 1997, 101(28): 5111-5116
[140] Martoňák R, Laio A, Parrinello M. Predicting crystal structures: the Parrinello-Rahman method revisited. Phys. Rev. Lett., 2003, 90(7): 075503
[141] Mujica A, Needs R J. Theoretical study of the high-pressure phase stability of GaP, InP, and InAs. Phys. Rev. B, 1997, 55(15): 9659-9670
[142] Pickard C J, Needs R J. Structures at high pressure from random searching. Phys. Status solidi B, 2009, 246(3): 536-540
[143] Segall M D, Lindan P L D, Probert M J, et al. First-principles simulation: ideas, illustrations and the CASTEP code. J. Phys.: Condens. Matter, 2002, 14(11): 2717-2744
[144] Payne M C, Teter M P, Allen D C, et al. Iterative minimization techniques for ab initio total-energy calculations: molecular dynamics and conjugate gradients. Rev. Mod. Phys., 1992, 64(4): 1045-1097
[145] Milman V, Winkler B, White J A, et al. Electronic structure, properties, and phase stability of inorganic crystals: a pseudopotential plane-wave study. Int. J. Quantum Chem., 2000, 77(5): 895-910
[146] Kalpana G, Palanivel B, Rajagopalan M. Electronic structure and structural phase stability in BaS, BaSe, and BaTe. Phys. Rev. B, 1994, 50(17): 12318-12325
[147] Wu X, Dong Y H, Qin S, et al. First-principles study of the pressure-induced phase transition in CaTiO3. Solid State Commun., 2005, 136(7): 416-420
[148] Birch F. Finite strain isotherm and velocities for single-crystal and polycrystalline NaCl at high pressures and 300o K. J. Geophys. Res., 1978, 83(B3): 1257-1268
[149] Aronsson B, ?selius J. The crystal structure of Ru_2Si. Acta Chem. Scand., 1961, 15(1): 1571-1574
[150] Venturini G, Ijjaali I, Ressouche E, et al. Neutron diffraction study of the HoMnSi, LuMnSi and Sc_(0.9)Lu_(0.1)MnSi compounds. J. Alloys Compd., 1997, 256(1-2): 65-75
[151]沈学础.半导体光学性质.北京:科学出版社, 1992: 7-10
[152] Bisi O, Braicovich L, Carbone C, et al. Chemical bond and electronic states in calcium silicides: theory and comparison with synchrotron-radiation photoemission. Phys. Rev. B, 1989, 40(15): 10194-10209
[153] Lebègue S, Arnaud B, Alouani M. Calculated quasiparticle and optical properties of orthorhombic and cubic Ca_2Si. Phys. Rev. B, 2005, 72(8): 085103
[154] Daisuke N H, Asa S, Ritsuko N, et al. The stability and equation of state for the cotunnite phase of TiO_2 up to 70 GPa. Phys. Chem. Minerals, 2010, 37(3): 129-136
[155] Luo W, Yang S F, Wang Z C, et al. Structural phase transitions in brookite-type TiO_2 under high pressure. Solid State Commun., 2005, 133(1): 49-53
[156] Sasaki T. Stability of rutile-type TiO2 under high pressure. J. Phys.: Condens. Matter., 2002, 14(44): 10557
[157] Kessler J R, Monberg E, Nicol M. Study of fluorite and related divalentfluoride systems at high pressure by Raman spectroscopy. J. Chem. Phys., 1974, 60(12): 5057-5065
[158] Kourouklis G A, Anastassakis E. Pressure-induced Phase transition in SrF_2: a Raman study. Phys. Rev. B, 1986, 34(2): 1233-1237
[159] Léger J M, Haines J, Danneels C. Phase transition sequence induced by high-pressure in CaCl_2. J. Phys. Chem. Solids, 1998, 59(8): 1199-1204
[160] Bedford K L. Ab initio cluster calculations of the electronic structure of crystalline BeF_2. Solid State communications, 1983, 45(6): 487-490