Vibrational and coherence dynamics of molecules

TL;DR

This paper analytically explores vibrational and coherence dynamics in molecules, revealing how coherence-population entanglement influences relaxation times, population imbalance, and heat current, with predictions aligning with recent experimental data.

Contribution

It provides an exact analytical investigation of vibrational coherence and population dynamics, highlighting the role of coherence-population entanglement in molecular relaxation processes.

Findings

Coherence-population entanglement extends dephasing time $t_2$ and increases coherence amplitude.

Population imbalance is significantly amplified by coherence-population entanglement.

Predicted vibrational relaxation in water molecules matches recent experimental results.

Abstract

We {\it analytically} investigate the population and coherence dynamics and relaxations in the vibrational energy transport in molecules. The corresponding two time scales $t_1$ and $t_2$ are explored. Coherence-population entanglement is found to considerably promote the time scale $t_2$ 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 $t_1<t_2$. 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 D$_2$O. Finally we explore the coherence effect on the heat current at the macroscopic level.