Quantum decoherence: a consistent histories treatment of condensed-phase non-adiabatic quantum molecular dynamics

摘要

We address the issue of quanlum decoherence in mixed quantum classical .simulations. We demonstrate that restricting thet bath paths to single .sialioftacy path which connects an initial quantum slate to a final quantum state affects a coarse grainingof ihc quantum subspaee- which Icads-to a macroscopic loss of quanlum coherence. The coarse graining can be described in terms of reduction mappings of lite density matrix of the reduced quantum system + stationary bath path. Application of ihc present model to Various prototypical condensed-phase chemical problems reveals that non-adiabatieily is extremely sensitive lo the decoherence timescale. Furthermore, we derive how to obtain quantum coherence timcscales from'realistic mixed quantum classical simulations and use this information to compute the non-radiative lifetimes for an excess electron in llaO and DO. We demonstrate'Ihiil subtle differences in Ihc. quantum coherence limes provide a rationalization for a long-standing puzzle regauling the lack of experimentally observed isolopic dependence of the non-radiative lifetime of a photoexcited electron in H_2O and D_2O.