Exploring dielectric response of CO2-methanol mixtures: the impact of CO2 bending vibrations via molecular dynamics

Abstract

This study presents an accurate reproduction of the infrared spectrum associated with the O–C–O bending mode in the carbon dioxide (CO 2) molecule, employing the newly developed CO 2/ ϵ model. A comparative analysis is conducted between two molecular models for carbon dioxide: CO 2/TraPPEflex and CO 2/ ϵ. The latter demonstrates superior performance in reproducing and refining the dielectric constant. Following this, particular emphasis is placed on identifying suitable candidates for the investigation of binary mixtures involving CO 2 and methanol (CH 3OH). This preliminary stage aims to evaluate model transferability and to extract essential data for theoretical calculations. The accurate representation of electrical properties within individual components plays a pivotal role in determining the behavior of the mixture. In this context, three methanol models are employed: TraPPE, TraPPE2015, and MeOH-4P. The latter two have been carefully optimized to enhance the depiction of key physical properties, namely the dielectric constant ( ϵ), surface tension ( γ), and liquid-phase density ( ρ).