SiH分子特性和势能函数的外场效应
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摘要
设置不同的外电场参量,采用B3P86/cc-PV5Z方法优化计算,获得不同外电场中SiH分子的键长、偶极矩、振动频率和红外光谱等物理性质参数.在此基础上采用单双取代耦合团簇CCSD(T)方法和相同的基组,扫描计算单点能获得相关势能曲线.结果表明在外电场中物理性质参数和势能都发生了较大变化,且在反向电场中变化幅度更明显.为了分析外电场效应,本文引入偶极近似构建外电场中的势能函数模型,编制程序拟合对应的势能函数,得出拟合参数,进而计算临界离解电场参量,结果与数值计算和理论分析较为一致,误差都在4%以内,说明构建的模型是合理和可靠的.这为分析外电场中分子光谱、动力学特性和分子Stark效应冷却囚禁提供一定的理论和实验参考.
By setting different electric fields and adopting density functional B3P86/cc-PV5 Zmethod,the geometric structure of SiH molecule is optimized,and the bond lengths,dipole moments,vibration frequencies and other physical properties parameters are obtained.On the basis of adopting the energy of high precision coupled cluster CCSD(T)method and the same basis set to scan single point energies,the potential energy curves of different external fields are given.The results show that the physical properties parameters and potential energy values will change with the changes of external electric field,especially,of the reverse direction electric field.In order to get the critical dissociation electric parameter,the dipole approximation is adopted to construct potential model,then the model is put to fit the corresponding potential energy curve of external electric field.It is found that the fitted critical dissociation electric parameter is reasonably consistent with the numerical calculation;i.e.,the relative errors are also less than 4%.So the model constructed is reliable and accurate.These will provide some theoretical and experimental reference for the studies of molecular spectroscopy,dynamics and molecular cooling with Stark effect.
By setting different electric fields and adopting density functional B3P86/cc-PV5 Zmethod,the geometric structure of SiH molecule is optimized,and the bond lengths,dipole moments,vibration frequencies and other physical properties parameters are obtained.On the basis of adopting the energy of high precision coupled cluster CCSD(T)method and the same basis set to scan single point energies,the potential energy curves of different external fields are given.The results show that the physical properties parameters and potential energy values will change with the changes of external electric field,especially,of the reverse direction electric field.In order to get the critical dissociation electric parameter,the dipole approximation is adopted to construct potential model,then the model is put to fit the corresponding potential energy curve of external electric field.It is found that the fitted critical dissociation electric parameter is reasonably consistent with the numerical calculation;i.e.,the relative errors are also less than 4%.So the model constructed is reliable and accurate.These will provide some theoretical and experimental reference for the studies of molecular spectroscopy,dynamics and molecular cooling with Stark effect.
引文
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[20]黄多辉,王藩侯,万明杰,等.外场下SnS分子结构及其特性[J].物理学报,2013,62:013104.
[21]伍冬兰,涂娟,万慧军,等.NH分子特性和势能随外电场的变化规律[J].四川大学学报:自然科学版,2015,52:1063.
[22]伍冬兰,胡强林,万慧军,等.AlH自由基在外电场中的分子特性和势能函数[J].四川大学学报:自然科学版,2014,51:991.
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[28]蒋利娟,刘玉芳,刘振中,韩晓琴.SiX2(X=H,F)分子的结构与势能函数[J].物理学报,2009,58:201.
[2]Jasinski J M,Becerra R,Walsh R.Direct kinetic studies of silicon hydride radicals in the gas phase[J].Chem Rev,1995,95:1203.
[3]Douglas A E,Elliott G A.Laboratory investigations of the interstellar radio-frequency lines of CH and other molecules[J].Can J Phys,1965,43:496.
[4]Schadee A.An upper limit of the swan band intensity in a sunspot spectrum[J].Solar Phys,1970,15:345.
[5]Sauval A J.Identification of SiH lines in the solar disk spectrum[J].Solar Phys,1969,10:319.
[6]Jackson C V.The spectrum of silicon hydride[J].Proc R Soc London Ser A,1930,126:373.
[7]Mulliken R S.Note on the interpretation of certain2Δ,2Πbands of SiH[J].Phys Rev,1931,37:733.
[8]Wirsam B.Combined SCF and CI calculations of the spectrum of SiH[J].Chem Phys Lett,1971,10:180.
[9]Kalemos A,Mavridis A.An accurate description of the ground and excited states of SiH[J].J Chem Phys,2002,116:6529.
[10]Cade P E,Huo W M.Electronic structure of diatomic molecules.VI.A.Hartree-Fock wavefunctions and energy quantities for the ground states of the first-row hydrides,AH[J].J Chem Phys,1967,47:649.
[11]Huber K P,Herzberg G.Molecular spectra and molecular structure IV constants of diatomic molecules[M].New York:Van Nostrand Reinhold Company,1978.
[12]Ajitha D,Pal S.Dipole moments of open-shell radicals using an analytic linear response approach in the Fock space multi-reference coupled cluster method[J].Chem Phys Lett,1999,309:457.
[13]Allen W D,Schaefer H F.Geometrical structures,force constants,and vibrational spectra of SiH,SiH2,SiH3and SiH4[J].Chem Phys,1986,2:243.
[14]Jordan P C.Lower electronic levels of the radicals SiH,SiH2and SiH3[J].J Chem Phys,1966,44:3400.
[15]Lewerenz M,Bruna P J,Peyerimhoff S D,et al.Ab initio MRD-CI study of the electronic spectrum of SiH[J].Mol Phys,1983,49:1.
[16]宋晓书,杨向东,汪荣凯,等.SiH(SiD)自由基的分子结构和基态势能函数的理论研究[J].四川大学学报:自然科学版,2006,43:1083.
[17]熊宝库,冯一兵,汤清彬,等.SiH,SiD,SiT分子基态(X2П)的结构与解析势能函数[J].云南大学学:自然科学版,2008,30:484.
[18]冯兴,王红艳,朱正和,等.SiH和SiH2分子的结构与势能函数[J].四川大学学报:自然科学版,2008,45:375.
[19]Shi D H,Zhang J P,Sun J F,et al.Investigations on spectroscopic properties of SiH(X2П)radical using coupled-cluster theory in combination with the correlation-consistent quintuple basis set[J].J Mol Struct,2008,851:30.
[20]黄多辉,王藩侯,万明杰,等.外场下SnS分子结构及其特性[J].物理学报,2013,62:013104.
[21]伍冬兰,涂娟,万慧军,等.NH分子特性和势能随外电场的变化规律[J].四川大学学报:自然科学版,2015,52:1063.
[22]伍冬兰,胡强林,万慧军,等.AlH自由基在外电场中的分子特性和势能函数[J].四川大学学报:自然科学版,2014,51:991.
[23]Bethlem H L,Crompvoets F M H,Jongma R T,et al.Deceleration and trapping of ammonia using time-varying electric field[J].Phys Rev A,2002,65:0534161.
[24]朱正和.原子分子反应静力学[M].北京:科学出版社,1996.
[25]朱正和,俞华根.分子结构与分子势能函数[M].北京:科学出版社,1997.
[26]徐国亮,朱正和,马美仲,等.甲烷激发态外场效应[J].物理学报,2005,54:3087.
[27]Chaudhuri R K,Mudholkar A,Freed K F,et al.Application of the effective valence shell Hamiltonian method to accurate estimation of valence and Rydberg states oscillator strengths and excitation energies forπelectron systems[J].J Chem Phys,1997,106:9252.
[28]蒋利娟,刘玉芳,刘振中,韩晓琴.SiX2(X=H,F)分子的结构与势能函数[J].物理学报,2009,58:201.