Zhang Linyao, Shu Yinan, Sun Shaozeng, Truhlar Donald G
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin 150001, People's Republic of China.
Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, USA.
J Chem Phys. 2021 Mar 7;154(9):094310. doi: 10.1063/5.0037878.
We evaluate the effect of electronic decoherence on intersystem crossing in the photodynamics of thioformaldehyde. First, we show that the state-averaged complete-active-space self-consistent field electronic structure calculations with a properly chosen active space of 12 active electrons in 10 active orbitals can predict the potential energy surfaces and the singlet-triplet spin-orbit couplings quite well for CHS, and we use this method for direct dynamics by coherent switching with decay of mixing (CSDM). We obtain similar dynamical results with CSDM or by adding energy-based decoherence to trajectory surface hopping, with the population of triplet states tending to a small steady-state value over 500 fs. Without decoherence, the state populations calculated by the conventional trajectory surface hopping method or the semiclassical Ehrenfest method gradually increase. This difference shows that decoherence changes the nature of the results not just quantitatively but qualitatively.
我们评估了电子退相干对硫甲醛光动力学中系间窜越的影响。首先，我们表明，在10个活性轨道中选择12个活性电子的合适活性空间进行态平均完全活性空间自洽场电子结构计算，能够很好地预测CHS的势能面和单重态-三重态自旋-轨道耦合，并且我们使用这种方法通过混合衰减的相干切换（CSDM）进行直接动力学计算。我们通过CSDM或在轨迹表面跳跃中添加基于能量的退相干获得了相似的动力学结果，三重态的布居数在500飞秒内趋于一个小的稳态值。没有退相干时，通过传统轨迹表面跳跃方法或半经典埃伦费斯特方法计算的态布居数会逐渐增加。这种差异表明，退相干不仅在数量上而且在质量上改变了结果的性质。
