Configurational Temperature Control for Atomic and Molecular Systems

TL;DR

This paper introduces a new configurational temperature thermostat for molecular systems with constraints, capable of generating the canonical ensemble and compatible with molecular dynamics simulations.

Contribution

A novel configurational thermostat that maintains constraints, generates the canonical ensemble, and is closely related to the Nose-Hoover kinetic thermostat.

Findings

Thermostat accurately reproduces equilibrium properties.

Compatible with molecules with holonomic constraints.

Validated through simulations of n-decane molecules.

Abstract

A new configurational temperature thermostat suitable for molecules with holonomic constraints is derived. This thermostat has a simple set of motion equations, can generate the canonical ensemble in both position and momentum space, acts homogeneously through the spatial coordinates, and does not intrinsically violate the constraints. Our new configurational thermostat is closely related to the kinetic temperature Nose-Hoover thermostat with feedback coupled to the position variables via a term proportional to the net molecular force. We validate the thermostat by comparing equilibrium static and dynamic quantities for a fluid of n-decane molecules under configurational and kinetic temperature control. Practical aspects concerning the implementation of the new thermostat in a molecular dynamics code and the potential applications are discussed.