Energy transformation and dynamic properties of N,N-dimethylformamide aqueous solution under E/M field using NNVE MD simulations

Abstract

Nonequilibrium NVE (NNVE) molecular dynamics (MD) simulations have been performed to investigated the N,N-dimethylformamide aqueous solution in both the absence and presence of E/M field (E=5×108V/m, the microwave frequency are from 0 to 100GHz). The main target of this work is to explore the energy transformation and dynamic properties of DMF aqueous solution during the microwave heating process. The temperature variation, microwave heating rate and energy distribution have been obtained. The direct coupling of rotational motion, vibration and reorientation have been revealed during the microwave energy distribution, and there are two-thirds microwave energy are stored as the intermolecular energy. The structural characteristics are further obtained from the radial distribution functions, tetrahedral order parameters and hydrogen bond. Compare to the conventional heating, the molecular conformations show significant difference and the structure of aqueous solution is intensely disturbed. The apparent increase of diffusion coefficient discloses that high microwave frequency accelerates the molecules motion.