Systematic molecular dynamics studies of liquid N,N-dimethylformamide using optimized rigid force fields: Investigation of the thermodynamic, structural, transport and dynamic properties

The properties of the pure liquid N,N-dimethylformamide were investigated by means of microcanonical (NVE) and isothermal–isobaric (NPT) molecular dynamics simulation techniques. Previously proposed five- and six-interaction-site optimized potential models (OPLS) were employed to simulate the liquid at different state points and their properties were obtained and discussed. The results obtained have shown that these models, to a higher or lower degree, yield realistic descriptions of the liquid. We have found, however, that a systematic readjustment of the potential parameters is necessary in order to describe the liquid properties more accurately. Thus, a new six-interaction-site OPLS computational model for liquid N,N-dimethylformamide has been derived. It turns out that this model can describe not only the thermodynamic and structural properties but also the dynamic (single and Debye relaxation) and the transport properties (self-diffusion, shear viscosity) of the system with good accuracy in the entire temperature range at normal pressure.