Examination of the applicability of multicomponent quantum mechanics to infrared spectroscopy calculations

IF 2.4 3区化学 Q4 CHEMISTRY, PHYSICAL

Chemical Physics Pub Date : 2025-09-06 DOI:10.1016/j.chemphys.2025.112937

Kazuki Kataoka, Yusuke Kanematsu, David S. Rivera Rocabado, Takayoshi Ishimoto

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引用次数: 0

Abstract

Quantum mechanics (QM) calculations of infrared spectra based on the Born–Oppenheimer and harmonic oscillator approximations cause errors depending on the level of the electronic structure calculation and the anharmonicity of the potential energy surface. Errors owing to anharmonicity are particularly strong for vibrations involving hydrogen nuclei with large quantum fluctuations. A possible solution to this issue is to apply multicomponent QM (MC_QM), which extends conventional QM calculations to quantum MC systems to enable the analysis of H/D isotope effects by treating nuclei as quantum particles, such as electrons. To investigate the suitability of MC_QM for infrared spectroscopy, this study calculated the vibrational frequencies of several H/D substituents using conventional QM and MC_QM methods and compared them with the corresponding experimental values. Results demonstrate that the MC_QM values exhibit improved reproducibility compared to the experimental values by incorporating nuclear quantum effects.

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检验多组分量子力学在红外光谱计算中的适用性

基于Born-Oppenheimer和谐振子近似的红外光谱量子力学（QM）计算会产生误差，这取决于电子结构计算的水平和势能面的非调和性。对于涉及具有大量子涨落的氢原子核的振动，由非调和性引起的误差特别强。这个问题的一个可能的解决方案是应用多组分QM (MC_QM)，它将传统的QM计算扩展到量子MC系统，通过将原子核当作量子粒子，如电子，来分析H/D同位素效应。为了研究MC_QM在红外光谱中的适用性，本研究分别用常规QM和MC_QM方法计算了几种H/D取代基的振动频率，并与相应的实验值进行了比较。结果表明，与实验值相比，加入核量子效应后，MC_QM值具有更好的可重复性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Chemical Physics 化学-物理：原子、分子和化学物理

CiteScore

4.60

自引率

4.30%

发文量

278

审稿时长

39 days

期刊介绍： Chemical Physics publishes experimental and theoretical papers on all aspects of chemical physics. In this journal, experiments are related to theory, and in turn theoretical papers are related to present or future experiments. Subjects covered include: spectroscopy and molecular structure, interacting systems, relaxation phenomena, biological systems, materials, fundamental problems in molecular reactivity, molecular quantum theory and statistical mechanics. Computational chemistry studies of routine character are not appropriate for this journal.