Ab Initio Multiple Spawning Dynamics Using Multi-State Second-Order Perturbation Theory

详细信息    查看全文

• 作者：Hongli Tao ; Benjamin G. Levine ; Todd J. Martnez
• 刊名：Journal of Physical Chemistry A
• 出版年：2009
• 出版时间：December 10, 2009
• 年：2009
• 卷：113
• 期：49
• 页码：13656-13662
• 全文大小：261K
• 年卷期：v.113,no.49(December 10, 2009)
• ISSN：1520-5215

文摘

We have implemented multi-state second-order perturbation theory (MS-CASPT2) in the ab initio multiple spawning (AIMS) method for first-principles molecular dynamics including nonadiabatic effects. The nonadiabatic couplings between states are calculated numerically using an efficient method which requires only two extra energy calculations per time step. As a representative example, we carry out AIMS-MSPT2 calculations of the excited state dynamics of ethylene. Two distinct types of conical intersections, previously denoted as the twisted-pyramidalized and ethylidene intersections, are responsible for ultrafast population transfer from the excited state to the ground state. Although these two pathways have been observed in prior dynamics simulations, we show here that the branching ratio is affected by dynamic correlation with the twisted-pyramidalized intersection overweighting the ethylidene-like intersection during the decay process at the AIMS-MSPT2 level of description.