Nuclear and electronic wave functions acquire a geometric phase (GP) when the system encircles a point of degeneracy in potential energy surfaces (e.g., conical intersection (CIs)). To accurately model nonadiabatic dynamics near CIs, molecular dynamics simulations need to consider GP effects. Mixed quantum-classical (MQC) approaches, surface-hopping and Ehrenfest methods, are used ubiquitously for on-the-fly simulations of nonadiabatic processes in large systems. Although these methods do not consider the GP explicitly, two-dimensional linear vibronic coupling models of pyrazine molecule, bis(methylene) adamantyl and butatriene cations, show that MQC methods can reproduce exact short-time quantum dynamics of radiationless electronic transitions. Our further analysis reveals how MQC methods can effectively mimic some quantum GP effects in excited state dynamics using classical mechanics.

Capturing geometric phase effects by mixed quantum-classical methods

249th National Meeting (2015)

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