Analysis of the Proton Transfer Bands in the Infrared Spectra of Linear N 2 H + ···OC and N 2 D + ···OC Complexes Using Electric Field-Driven Classical Trajectories
Analysis of the Proton Transfer Bands in the Infrared Spectra of Linear N 2 H + ···OC and N 2 D + ···OC Complexes Using Electric Field-Driven Classical Trajectories
复制标题
使用电场驱动经典轨迹分析线性 N 2 H····OC 和 N 2 D····OC 配合物的红外光谱中的质子传递带
DOI：
10.1021/acs.jpca.0c06756
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Kaledin, Martina
中科院分区：
文献类型：
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作者：
Boutwell, Dalton;Okere, Onyinye;Omodemi, Oluwaseun;Toledo, Alexander;Barrios, Antonio;Olocha, Monique;Kaledin, Martina
在这项工作中，我们描述了涉及流动质子的氢键离子分子复合物的红外（IR）光谱的从头计算和分配：线性N2H+·OC和N2D+·OC复合物。考虑到描述流质子动力学，特别是其红外活性的挑战，我们使用电场驱动的经典轨迹，即我们近年来针对类似应用开发的驱动分子动力学（DMD）方法，并结合高级电子结构理论。也就是说，我们提出了一种经过修改且数字高效的 DMD 实现，专门用于直接（或“即时”）计算，我们在势能面 (PES) 的 MP2-F12/AVDZ 理论水平和偶极矩面 (DMS) 的 MP2/AVDZ 理论水平上进行。对涉及 H+/D+ 的高通量振动的 PES、DMS 以及 DMS 一阶导数（称为驱动力）的时间依赖性的详细分析表明，强非谐波 PES 和非线性 DMS 会产生非常复杂的振动谱。有趣的是，经典轨迹揭示了光谱质子转移部分的双峰，两个峰分别位于 1800 和 1980 cm-1 处。我们发现它们的共同强度是由于 H+ 平行拉伸基波和 H+ 垂直弯曲泛音在经典极限内的类费米共振相互作用所致。在 1360 和 1460 cm–1 的氘化物质中也观察到了这种双峰。
In this work, we describe ab initio calculations and assignment of infrared (IR) spectra of hydrogen-bonded ion–molecular complexes that involve a fluxional proton: the linear N2H+···OC and N2D+···OC complexes. Given the challenges of describing fluxional proton dynamics and especially its IR activity, we use electric field-driven classical trajectories, i.e., the driven molecular dynamics (DMD) method that was developed by us in recent years and for similar applications, in conjunction with high-level electronic structure theory. Namely, we present a modified and a numerically efficient implementation of DMD specifically for direct (or “on the fly”) calculations, which we carry out at the MP2-F12/AVDZ level of theory for the potential energy surface (PES) and MP2/AVDZ for the dipole moment surfaces (DMSs). Detailed analysis of the PES, DMS, and the time-dependence of the first derivative of the DMS, referred to as the driving force, for the highly fluxional vibrations involving H+/D+revealed that the strongly non-harmonic PES and non-linear DMS yield remarkably complex vibrational spectra. Interestingly, the classical trajectories reveal a doublet in the proton transfer part of the spectrum with the two peaks at 1800 and 1980 cm–1. We find that their shared intensity is due to a Fermi-like resonance interaction, within the classical limit, of the H+parallel stretch fundamental and an H+perpendicular bending overtone. This doublet is also observed in the deuterated species at 1360 and 1460 cm–1.