Dynamic signatures of electronically nonadiabatic coupling in sodium hydride: a rigorous test for the symmetric quasi-classical model applied to realistic, ab initio electronic states in the adiabatic representation
Dynamic signatures of electronically nonadiabatic coupling in sodium hydride: a rigorous test for the symmetric quasi-classical model applied to realistic, ab initio electronic states in the adiabatic representation
复制标题
氢化钠中电子非绝热耦合的动态特征：对应用于绝热表示中的真实从头电子态的对称准经典模型的严格测试
DOI：
10.1039/d1cp04090a
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发表时间：
2022
影响因子：
3.3
通讯作者：
Cotton, Stephen J.
中科院分区：
文献类型：
--
作者：
Talbot, Justin J.;Head-Gordon, Martin;Miller, William H.;Cotton, Stephen J.
气相氢化钠（NaH）呈现出看似简单的电子结构，使其成为从计算和实验角度详细研究非绝热分子动力学的潜在可处理系统。单振动自由度，以及由激发态产生的具有相当大的离子特征的强非绝热耦合，提供了一个现实的化学系统来测试准经典方法的准确性，以模拟种群动力学，其结果可直接与量子力学基准进行比较。利用模拟的泵-探针型实验，本研究通过对称准经典迈耶-米勒（SQC/MM）、Ehrenfest和精确量子动力学，在现实的从头算势能表面上，通过避免的NaH交叉，给出了人口转移的计算预测。人口转移的主要驱动力来自于嵌入在近解离C1Σ+振动态流形中的D1Σ+绝热态的地面振动水平。当通过尖锐局域一阶导数耦合耦合时，根据初始激发的振动波包，大多数人口在t = 15和t = 30 fs之间转移。虽然量子力学效应是由于纳米粒子的质量降低而产生的，但SQC/MM和Ehrenfest模型对量子动力学基准的预测都表现得非常好。此外，采用变分本征求解方法对非绝热耦合状态下的振动结构进行了分析。
Sodium hydride (NaH) in the gas phase presents a seemingly simple electronic structure making it a potentially tractable system for the detailed investigation of nonadiabatic molecular dynamics from both computational and experimental standpoints. The single vibrational degree of freedom, as well as the strong nonadiabatic coupling that arises from the excited electronic states taking on considerable ionic character, provides a realistic chemical system to test the accuracy of quasi-classical methods to model population dynamics where the results are directly comparable against quantum mechanical benchmarks. Using a simulated pump–probe type experiment, this work presents computational predictions of population transfer through the avoided crossings of NaH via symmetric quasi-classical Meyer–Miller (SQC/MM), Ehrenfest, and exact quantum dynamics on realistic, ab initio potential energy surfaces. The main driving force for population transfer arises from the ground vibrational level of the D1Σ+ adiabatic state that is embedded in the manifold of near-dissociation C1Σ+ vibrational states. When coupled through a sharply localized first-order derivative coupling most of the population transfers between t = 15 and t = 30 fs depending on the initially excited vibronic wavepacket. While quantum mechanical effects are expected due to the reduced mass of NaH, predictions of the population dynamics from both the SQC/MM and Ehrenfest models perform remarkably well against the quantum dynamics benchmark. Additionally, an analysis of the vibronic structure in the nonadiabatically coupled regime is presented using a variational eigensolver methodology.