Nonadiabatic excited-state molecular dynamics: Treatment of electronic decoherence

摘要: Within the fewest switches surface hopping (FSSH) formulation, a swarm of independent trajectories is propagated and equations motion for quantum coefficients are evolved coherently along each nuclear trajectory. That is, phase factors, or amplitudes, retained. At region strong coupling, trajectory can branch into multiple wavepackets. Directly following hop, two wavepackets remain in nonadiabatic coupling continue exchanging population. After these have sufficiently separated space, they should begin to evolve independently from one another, process known as decoherence. Decoherence not accounted standard algorithm leads internal inconsistency. FSSH designed ensure that at any time, fraction classical evolving on state equal average probability state. However, many systems this consistency requirement violated. Treating decoherence an inherent problem be addressed by implementing some form correction algorithm. In study, we implemented forms instantaneous procedure where reinitialized hops. We also test energy-based (EDC) scheme proposed Granucci et al. related version time taken Truhlar's Coherent Switching with Decay Mixing method. The sensitivity EDC results changes parameters evaluated. application computationally inexpensive ad hoc methods demonstrated simulation nonradiative relaxation conjugated oligomer systems, specifically poly-phenylene vinylene ethynylene. find been used successfully treating small do necessarily translate large polyatomic their success depends particular system under study.