The vibrational spectrum of crystalline benzoic acid: Inelastic neutron scattering and density functional theory calculations
The vibrational spectrum of crystalline benzoic acid: Inelastic neutron scattering and density functional theory calculations
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结晶苯甲酸的振动谱：非弹性中子散射和密度泛函理论计算
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
H. Trommsdorff
中科院分区：
文献类型：
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作者：
M. Plazanet;N. Fukushima;Mark R. Johnson;A. J. Horsewill;H. Trommsdorff
通过非弹性中子散射记录了苯甲酸（BA）晶体的几种同位素异构体的振动光谱，并将其与不同势能表面（PES）计算的光谱进行了比较。这些 PES 是在使用不同代码和不同级别的基函数对单体、孤立的二聚体和晶体进行的量子化学密度泛函理论 (DFT) 计算的调和近似内获得的。在不细化力常数的情况下，计算光谱和观测光谱之间的一致性已经足以明确分配所有振动模式。通过定期 DFT 计算获得了最佳一致性。计算频率与观测频率之间最显着的差异出现在面外 O-H 弯曲模式中。对于这些模式（以及面内弯曲和 O-H 拉伸模式），计算了电势的非调和性，并且显示非调和校正可解释大约十分之一...
Vibrational spectra of several isotopomers of benzoic acid (BA) crystals have been recorded by inelastic neutron scattering and are compared with spectra calculated for different potential energy surfaces (PES). These PES were obtained within the harmonic approximation from quantum chemical density functional theory (DFT) calculations made for the monomer, the isolated dimer, and the crystal using different codes and different levels of basis functions. Without refinement of the force constants, agreement between calculated and observed spectra is already sufficient for an unambiguous assignment of all vibrational modes. The best agreement was obtained with periodic DFT calculations. The most prominent discrepancy between calculated and observed frequencies was found for the out-of-plane O–H bending modes. For these modes (as well as for the in-plane bending and the O–H stretching modes) the anharmonicity of the potential was calculated, and the anharmonic correction was shown to account for about one-thi...