The ab initio limit quartic force field of BH3

被引:53
作者
Schuurman, MS [1 ]
Allen, WD [1 ]
Schaefer, HF [1 ]
机构
[1] Univ Georgia, Ctr Computat Chem, Athens, GA 30602 USA
关键词
complete basis set (CBS) limit; quartic force field; vibrational perturbation theory (VPT2); ab initio fundamental frequencies; coupled-cluster theory;
D O I
10.1002/jcc.20238
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The complete quartic force field of BH3 has been converged to the ab initio limit by extrapolation of core-valence correlation-consistent basis set series (cc-pCVXZ, X = T, Q, 5) of all-electron CCSD(T) (coupled-cluster singles and doubles with perturbative triples) energy points. Additional computations including full coupled-cluster treatments through quadruple excitations (CCSDTQ), scalar relativistic effects, and diagonal Born-Oppenheimer corrections (DBOC) were concurrently executed. Within second-order vibrational perturbation theory (VPT2) our quartic force field yields the fundamental frequencies v(1) = 2502.3 cm(-1), v(2) = 1147.2 cm(-1), v(3) = 2602.1 cm(-1), and v(4) = 1196.5 cm(-1), in excellent agreement with observed gas-phase fundamentals, displaying a mean absolute error of only 0.3 cm(-1). Our converged prediction for the equilibrium bond length of BH3 is r(e) = 1.1867 angstrom. (c) 2005 Wiley Periodicals, Inc.
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页码:1106 / 1112
页数:7
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