Vibrational and coherence dynamics of molecules

We analytically investigate the population and coherence dynamics and relaxations in the vibrational energy transport in molecules. The corresponding two time scales t₁ and t₂ are explored. Coherence-population entanglement is found to considerably promote the time scale t₂ for dephasing and the amplitude of coherence. This is attributed to the suppression of the environment-induced drift force by coherence. Moreover the population imbalance (magnetization) is shown to be significantly amplified with the coherence-population entanglement. Contrary to the previous studies, we exactly elucidate a coherent process by showing t₁ < t₂. We predict the relaxation of vibrational and orientational dynamics of OH-stretching modes in agreement with the recent experiments, when applied to the water molecules dissolved in D₂O. Finally we explore the coherence effect on the heat current at the macroscopic level.