Exploring the conformational dynamics of alanine dipeptide in solution subjected to an external electric field: A nonequilibrium molecular dynamics simulation

TL;DR

This study uses nonequilibrium molecular dynamics to analyze how external electric fields influence the conformational behavior of alanine dipeptide in solution, revealing distinct dynamics and solvent effects.

Contribution

It introduces a procedure for temperature control in simulations under electric fields and explores conformational and solvent responses to both constant and oscillatory fields.

Findings

Different time-scales identified in conformational and dipole dynamics

Solvent structure remains largely unchanged under electric fields

Oscillatory fields induce non-trivial conformational fluxes

Abstract

In this paper, we investigate the conformational dynamics of alanine dipeptide under an external electric field by nonequilibrium molecular dynamics simulation. We consider the case of a constant and of an oscillatory field. In this context we propose a procedure to implement the temperature control, which removes the irrelevant thermal effects of the field. For the constant field different time-scales are identified in the conformational, dipole moment, and orientational dynamics. Moreover, we prove that the solvent structure only marginally changes when the external field is switched on. In the case of oscillatory field, the conformational changes are shown to be as strong as in the previous case, and non-trivial nonequilibrium circular paths in the conformation space are revealed by calculating the integrated net probability fluxes.