Depolarized Rayleigh Scattering from CO2: An Experimental and Molecular Dynamics Investigation

Abstract

AbstractA direct comparison of experimental depolarized Rayleigh spectra of CO2 with those obtained by molecular dynamics (MD) simulations at two different statepoints are reported. For the MD simulations a three Lennard‐Jones centres and central point quadrupole moment (3LJC + Q) interaction model has been used. Total depolarized spectra as well as their constituents (a) orientational, (b) collision induced, and (c) cross spectra were calculated for two polarizability models: In the first centre‐centre (C‐C) model the molecular polarizability is placed in the centre of the molecules whereas in the second site‐site (S‐S) model two partial polarizabilities are placed on the O atom sites. At the lower density the spectra resulting from both polarizability models compare well with the experimental spectrum. At the high density both model spectra noticeably deviate from the experimental one: the C‐C model spectrum giving the better description. This result is in contradiction to a previous investigation based on a two Lennard‐Jones centres potential. Thus any assessment of the relative merits of the two polarizability models seem to be premature at this stage since the role played by the interaction potential is not fully understood.