  Mixed-quantum-classical molecular dynamics simulation implies an effective
measurement on the electronic states owing to continuously tracking the atomic
forces.Based on this insight, we propose a quantum trajectory mean-field
approach for nonadiabatic molecular dynamics simulations. The new protocol
provides a natural interface between the separate quantum and classical
treatments, without invoking artificial surface hopping algorithm. Moreover, it
also bridges two widely adopted nonadiabatic dynamics methods, the Ehrenfest
mean-field theory and the trajectory surface-hopping method. Excellent
agreement with the exact results is illustrated with representative model
systems, including the challenging ones for traditional methods.
