McLaurin Patrick M, Morales Jorge A
Department of Chemistry and Biochemistry, Texas Tech University, PO Box 41061, Lubbock, TX 79409-1061, USA.
Phys Chem Chem Phys. 2020 Sep 16;22(35):19549-19559. doi: 10.1039/d0cp03722b.
The simplest-level electron nuclear dynamics (SLEND) method with the coherent-states (CSs) quantum reconstruction procedure (CSQRP) is applied to the scattering system H+ + CO2 (000) → H+ + CO2 (v1v2v3) at ELab = 20.5-30 eV. Relevant for astrophysics, atmospheric chemistry and proton cancer therapy, this system undergoes collision-induced vibrational excitations in CO2. SLEND is a time-dependent, variational, direct, and non-adiabatic method that adopts a classical-mechanics description for nuclei and a single-determinantal wavefunction for electrons. The CSQRP employs the canonical CS to reconstruct quantum state-to-state vibrational properties from the SLEND classical nuclear dynamics. Overall, the calculated collision-induced vibrational properties agree well with experimental data. SLEND total differential cross sections (DCSs) agree remarkably well with their experimental counterparts and accurately display rainbow scattering angles structures. SLEND averaged target excitation energies for vibrational + rotational and rotational motions exhibit reasonable and good agreements with experimental data, respectively. These properties show that rotational excitation is low and that the asymmetric stretch normal mode of CO2 is much more excited than the others. SLEND/CSQRP state-to-state vibrational DCSs agree reasonably well with the sparse experimental data for final states v1v2v3 = 000-002, but less satisfactorily for 003. These DCSs also accurately display rainbow scattering angles structures. Finally, SLEND/CSQRP vibrational proton energy loss spectra agree remarkably well with their experimental counterparts for various final vibrational states of CO2, collisions energies and scattering angles. Present results demonstrate the accuracy of SLEND/CSQRP to predict state-to-state vibrational properties in scattering systems with multiple normal modes.
将具有相干态（CSs）量子重构程序（CSQRP）的最简级电子-核动力学（SLEND）方法应用于散射系统H⁺ + CO₂(000) → H⁺ + CO₂(v₁v₂v₃)，实验室能量ELab = 20.5 - 30 eV。该系统与天体物理学、大气化学和质子癌症治疗相关，会在CO₂中引发碰撞诱导的振动激发。SLEND是一种含时、变分、直接且非绝热的方法，它对原子核采用经典力学描述，对电子采用单行列式波函数。CSQRP利用正则CS从SLEND经典核动力学中重构量子态到态的振动特性。总体而言，计算得到的碰撞诱导振动特性与实验数据吻合良好。SLEND的总微分截面（DCSs）与其实验对应值非常吻合，并准确显示出彩虹散射角结构。SLEND对振动 + 转动以及转动运动的平均靶激发能分别与实验数据呈现出合理且良好的吻合。这些特性表明转动激发较低，且CO₂的不对称伸缩简正模式比其他模式激发程度高得多。SLEND/CSQRP态到态振动DCSs与终态v₁v₂v₃ = 000 - 002的稀疏实验数据吻合较好，但对于003的吻合度稍差。这些DCSs也准确显示出彩虹散射角结构。最后，SLEND/CSQRP振动质子能量损失谱与CO₂各种终态振动、碰撞能量和散射角的实验对应谱非常吻合。目前的结果证明了SLEND/CSQRP在预测具有多个简正模式的散射系统中态到态振动特性方面的准确性。
