摘要
运用二次组态相关(QCISD)方法,分别选用6-311++G(3df,3pd)和D95(3df,3pd)基组,对BH2和AlH2分子的结构进行了优化计算,得到BH2分子的稳态结构为C2v构型,电子态为2A1、平衡核间距RBH=0.1187nm、键角∠HBH=128.791°、离解能De=3.65eV、基态振动频率ν1(a1)=1020.103cm-1,ν2(a1)=2598.144cm-1,ν3(b2)=2759.304cm-1.AlH2分子的稳态结构也为C2v构型,电子态为2A1、平衡核间距RAlH=0.1592nm、键角∠HAlH=118.095°、离解能De=2.27eV、基态振动频率ν1(a1)=780.81cm-1,ν2(a1)=1880.81cm-1,ν3(b2)=1910.46cm-1.采用多体项展式理论推导了基态BH2和AlH2分子的解析势能函数,其等值势能图准确再现了BH2和AlH2分子的结构特征及其势阱深度与位置.分析讨论势能面的静态特征时得到BH+H→BH2反应中存在鞍点,活化能为150.204kJ/mol;AlH+H→AlH2反应中也存在鞍点,活化能为54.8064kJ/mol.
Quadratic configuration interaction （QCISD） method has been used to optimize the possible ground-state structures of BH2 and AlH2 molecules. The results show that the ground state of BH2 molecule has C2, symmetry and is in the 2A1 state. The parameters of structure and the harmonic frequencies are RBH = 0.1187nm, ∠HBH = 128.7914°, De = 3.65eV, v1 （ α1 ） = 1020. 103 cm ^-1 , 92 （ α1 ） = 2598. 144cm ^-1 and v3 （ b2 ） = 2759.304cm ^-1 , respectively. The results also show that the ground state of AlH2 molecule has C2v symmetry and is in the 2A1 state. The parameters of structure and the harmonic frequencies are of RMH = 0. 1592nm, ∠HAlH = 118.095°, De = 2.27eV, v1（ α1 ） = 780.81cm^-1 , v2 （ α1 ） = 1880.81cm^-1 and v3 （ b2 ） = 1910.46cm^-1 , respectively. The potential energy functions of BH2 and AlH2 have been derived from the many-body expansion theory. The potential energy functions describe correctly the configurations and the dissociation energies of the two ground-state molecules. Molecular reaction kinetics of BH ＋ H and AlH ＋ H based on the potential energy functions is discussed briefly.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2006年第9期4490-4495,共6页
Acta Physica Sinica
基金
国家自然科学基金(批准号:10574039)资助的课题.~~
