Algorithms for Sampling a Quantum Microcanonical Ensemble of Harmonic Oscillators at Potential Minima and Conical Intersections

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• 作者：Kyoyeon Park ; Joshua Engelkemier ; Maurizio Persico ; Paranjothy Manikandan ; William L. Hase
• 刊名：Journal of Physical Chemistry A
• 出版年：2011
• 出版时间：June 23, 2011
• 年：2011
• 卷：115
• 期：24
• 页码：6603-6609
• 全文大小：916K
• 年卷期：v.115,no.24(June 23, 2011)
• ISSN：1520-5215

文摘

Algorithms are presented for sampling quantum microcanonical ensembles for a potential energy minimum and for the conical intersection at the minimum energy crossing point of two coupled electronic states. These ensembles may be used to initialize trajectories for chemical dynamics simulations. The unimolecular dynamics of a microcanonical ensemble about a potential energy minimum may be compared with the dynamics predicted by quantum Rice鈥揜amsperger鈥揔assel鈥揗arcus (RRKM) theory. If the dynamics is non-RRKM, it will be of particular interest to determine which states have particularly long lifetimes. Initializing a microcanonical ensemble for the electronically excited state at a conical intersection is a model for electronic nonadiabatic dynamics. The trajectory surface-hopping approach may be used to study the ensuing chemical dynamics. A strength of the model is that zero-point energy conditions are included for the initial nonadiabatic dynamics at the conical intersection.