Intramolecular Proton Transfer in the Hydrogen Oxalate Anion and the Cooperativity Effects of the Low-Frequency Vibrations: A Driven Molecular Dynamics Study
Intramolecular Proton Transfer in the Hydrogen Oxalate Anion and the Cooperativity Effects of the Low-Frequency Vibrations: A Driven Molecular Dynamics Study
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草酸氢阴离子中的分子内质子转移和低频振动的协同效应：驱动分子动力学研究
DOI：
10.1021/acs.jpca.1c09686
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Kaledin, Martina
中科院分区：
文献类型：
--
作者：
Boutwell, Dalton;Pierre-Jacques, Dominick;Cochran, Olivia;Dyke, Jason;Salazar, Dayana;Tyler, Ciara;Kaledin, Martina
本文报道了在MP2/aug-cc-pVDZ理论水平上草酸氢阴离子的第一性原理分子动力学（MD）和偶极子驱动分子动力学（μ-DMD）模拟。我们研究了OH拉伸带（即跨越2900-3100 cm - 1范围的基本带和几个组合带）和几个低频弯曲和拉伸基本模式之间的振动耦合的作用。300 ~ 825 cm - 1之间的低频模式在质子转移运动中起关键作用。co2、CCO弯曲振动和CC拉伸振动的强烈参与表明，这些大振幅运动导致O···O距离缩短，从而促进H+通过超过3.4 kcal/mol势垒转移到其他氧。共振μ-DMD轨迹分析表明，825 cm-1附近的复杂光谱特征与425 cm-1两个量子的泛音以及300 cm-1和575 cm-1 CCO弯曲的低频组合带紧密对应。μ-DMD表明，在这些模式组合下激发系统比在OH基模下激发系统能产生更快的势垒激活。
We report first-principles molecular dynamics (MD) and dipole-driven molecular dynamics (μ-DMD) simulations of the hydrogen oxalate anion at the MP2/aug-cc-pVDZ level of theory. We examine the role of vibrational coupling between the OH stretching bands, that is, the fundamental and a few combination bands spanning the 2900–3100 cm–1range, and several of the low-frequency bending and stretching fundamental modes. The low-frequency modes between 300 and 825 cm–1play a crucial role in the proton-transfer motion. Strong involvement of CO2and CCO bending and the CC stretching vibrations indicate that these large amplitude motions cause the shortening of the O···O distance and thus promote H+transfer to the other oxygen by bringing it over the 3.4 kcal/mol barrier. Analysis of resonant μ-DMD trajectories shows that the complex spectral feature near 825 cm–1, closely corresponding to both an overtone of two quanta of 425 cm–1and a combination band of low-frequency CO2rocking (300 cm–1) and CCO bending (575 cm–1) modes, is involved in the proton transfer. μ-DMD shows that exciting the system at these mode combinations leads to faster barrier activation than exciting at the OH fundamental mode.