PO_X(X=1,2)的光谱常数与从头算势能曲线
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摘要
采用从头算的多种方法对PO、 PO_2自由基的基态结构进行优化计算,结果表明:使用密度泛函(DFT)方法计算的结果最接近实验值.对PO双原子分子优选6-311G(3df)基组进行计算、扫描并拟合.对PO_2三原子分子优选出6-311+G(3df)方法计算结构参数、谐振频率、离解能及力常数,借助多体项展式理论导出PO_2自由基的势能函数并绘制等值势能图.发现:PO_2自由基的对称伸缩振动和旋转势能图中,在O+PO→OPO反应通道上都有鞍点出现,O原子需要越过0.55 eV的能量才能生成稳定的PO_2自由基.要形成PO_2自由基只能通过两等价的通道越过势垒才能形成.
Many methods are used to optimize possible ground state structures of PO、 PO_2 with multi-basis set. It was found that DFT method is the most suitable for calculation of PO,PO_2. For PO free radical, M-S potential energy functional constants are calculated with 6-311 G(3 df). For PO_2 free radical, equilibrium structure, harmonic frequency, dissociation energy and force constant are calculated with 6-311+G(3 df). Potential energy functions of PO_2 are derived from many-body expansion theory. It was pointed out that there is a saddle point in reaction kinetics O+PO→OPO, and a stable PO_2 molecule could be formed as O atom with energy surpassing 0.55 eV. A stable PO_2 molecule could be formed through two equivalent channels over barrier.
Many methods are used to optimize possible ground state structures of PO、 PO_2 with multi-basis set. It was found that DFT method is the most suitable for calculation of PO,PO_2. For PO free radical, M-S potential energy functional constants are calculated with 6-311 G(3 df). For PO_2 free radical, equilibrium structure, harmonic frequency, dissociation energy and force constant are calculated with 6-311+G(3 df). Potential energy functions of PO_2 are derived from many-body expansion theory. It was pointed out that there is a saddle point in reaction kinetics O+PO→OPO, and a stable PO_2 molecule could be formed as O atom with energy surpassing 0.55 eV. A stable PO_2 molecule could be formed through two equivalent channels over barrier.
引文
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[11] ROBERT W, MATTHEW M. Ledrews absorption spectra of the phosphorus oxide (PO2 and PO3) radicals in solid argon[J]. J Phys Chem, 1989, 93: 126-129.
[12] STEPHEN A, JARRETT S, LAN H H, Lan R G. Ab initio calculations of the structure and infrared spectrum of PO2 , P2O and P4O[J]. Chem Phys, 1990, 140: 27-33.
[13] QIAN H B, DAVIES P B, AHMAD I K, HAMILTON P A. Detection of the infrared laser spectrum of the PO2 radical in the gas phase[J]. Chem Phys Lett,1995, 235: 255-259.
[14] MICHAEL A L, KRISTIAN J H, PAUL B D. Infrared diode laser spectroscopy of the ν3 fundamental band of the PO2 free radical[J]. J Mole Spect, 2011, 269: 61-76.
[15] ZENG H, ZHAO J. Theoretical study of structure and analytic potential energy function for the ground state of PO2 molecule[J]. Chinese Phys B, 2012, 21: 078202
[16] SHI D H, LIU H, SUN J F, ZHU Z L, LIU Y F. Investigations on molecular structure and analytic potential energy function of the AsH(X3Σ-) and AsH2(C2v,X2B1) radicals[J]. Acta Phys Sin, 2010.59: 227-233.
[17] QI C H, WANG M S, YANG C L, XU Q. Theoretical study of spectroscopic constants and anharmonic force field of PO2 free radical[J]. J Atom Mol Phy, 2014.31: 371-376.
[18] ZHU Z H. Atomic and molecular reaction static[M]. Beijing: Science Press, 1996:156.
[19] ALFREDO A, MIGUEL P. A new functional form to obtain analytical potentials of triatomic molecules[J].J Chem Phys,1992,96: 1265-1275.
[20] FRANCISCC J. An ab initio study of the structure and stability of Cl-HOCl anionic complex[J]. Chem Phys Lett,1996,260: 485-491.
[21] HAN X Q, JIANG L J, LIU Y F. The structure and potential energy function of MgB and MgB2(1A1)[J]. Acta Phys Sin, 2009 59: 1000.
[22] XIAO X J, HAN X Q, LIU Y F. The structure and potential energy function of XF2(X=B,N) molecular ground state[J]. Acta Phys Sin, 2011, 60: 063102.
[2] HAN X Q, XIAO X J, LIU Y F. The ab initio and potential energy curve of OH、OCl and HOCl(1A′)[J]. Acta Phys Sin, 2012, 61(16): 163101(1-7).
[3] MORRISON M A, SUN Weiguo. Computational methods for electron-molecule collisions[M]. HUO W M, GIANTURCO F A eds. New York: Plenum, 1995.
[4] HUBER K P, HERZBERG G. Molecular spectrum and molecular structure (IV)[M]. New York: Van Nostrand, 1979.
[5] CAI Z L, GERHARD H, ROBERT B. Ab initio study of the electronic spectrum of the PO2 radical[J]. Chem Phys Letts, 1996, 255: 350-356.
[6] LESTE A, ROBERT W. Matrix reactions of oxygen atoms with P4. Infrared spectra of P4O, P2O, PO and PO2[J]. J Am Chem Soc, 1988, 110: 5605-5611.
[7] BREWER L, ROSENBIATT G. Dissociation energies of gaseous metal dioxides[J]. Chem Rev, 1961,61: 257-263.
[8] DROWART B J, MYERS C E, SZWAR R, VANDER A A. Determination by the mass spectrometric Knudsen cell method of the atomization energies of the molecules PO and PO2[J]. J Chem Soc Faraday Trans,1972, 68: 1749-1757.
[9] LAWRENCE L, LOHR. A theoretical study of the gaseous oxides phosphorus dioxide (PO2) and phosphorus monoxide (PO), their anions, and their role in the combustion of phosphorus and phosphine[J]. J Phys Chem, 1984, 88: 5569-5574.
[10] KAWAGUCHI K, SAITO S, HIRTOA E, OHASHI N. Far-infrared laser magnetic resonance detection and microwave spectroscopy of the PO2 radical[J]. J Chem Phys, 1985, 82: 4893-4902.
[11] ROBERT W, MATTHEW M. Ledrews absorption spectra of the phosphorus oxide (PO2 and PO3) radicals in solid argon[J]. J Phys Chem, 1989, 93: 126-129.
[12] STEPHEN A, JARRETT S, LAN H H, Lan R G. Ab initio calculations of the structure and infrared spectrum of PO2 , P2O and P4O[J]. Chem Phys, 1990, 140: 27-33.
[13] QIAN H B, DAVIES P B, AHMAD I K, HAMILTON P A. Detection of the infrared laser spectrum of the PO2 radical in the gas phase[J]. Chem Phys Lett,1995, 235: 255-259.
[14] MICHAEL A L, KRISTIAN J H, PAUL B D. Infrared diode laser spectroscopy of the ν3 fundamental band of the PO2 free radical[J]. J Mole Spect, 2011, 269: 61-76.
[15] ZENG H, ZHAO J. Theoretical study of structure and analytic potential energy function for the ground state of PO2 molecule[J]. Chinese Phys B, 2012, 21: 078202
[16] SHI D H, LIU H, SUN J F, ZHU Z L, LIU Y F. Investigations on molecular structure and analytic potential energy function of the AsH(X3Σ-) and AsH2(C2v,X2B1) radicals[J]. Acta Phys Sin, 2010.59: 227-233.
[17] QI C H, WANG M S, YANG C L, XU Q. Theoretical study of spectroscopic constants and anharmonic force field of PO2 free radical[J]. J Atom Mol Phy, 2014.31: 371-376.
[18] ZHU Z H. Atomic and molecular reaction static[M]. Beijing: Science Press, 1996:156.
[19] ALFREDO A, MIGUEL P. A new functional form to obtain analytical potentials of triatomic molecules[J].J Chem Phys,1992,96: 1265-1275.
[20] FRANCISCC J. An ab initio study of the structure and stability of Cl-HOCl anionic complex[J]. Chem Phys Lett,1996,260: 485-491.
[21] HAN X Q, JIANG L J, LIU Y F. The structure and potential energy function of MgB and MgB2(1A1)[J]. Acta Phys Sin, 2009 59: 1000.
[22] XIAO X J, HAN X Q, LIU Y F. The structure and potential energy function of XF2(X=B,N) molecular ground state[J]. Acta Phys Sin, 2011, 60: 063102.