Molecular dynamics of CH2Cl2: temperature dependences of the far infra-red spectrum. Part 1: experimental and simulation

Abstract

The temperature dependence of the rotational diffusion in liquid CH₂Cl₂ has been measured in the far infrared from 10 to 220 cm⁻¹ and 177K to 313K (f.p. to b.p. at 1bar). The results are interpreted at 177K and 293K with a molecular dynamics simulation using a 5 × 5 atom-atom potential with charge-charge electrodynamics. The simulation reproduces the basic features of the spectra but some experimental detail of the dependency of

_max, the far infrared peak frequency, on temperature is not followed by the simulation. The situation can be improved by accurately measuring the second dielectric virial coefficient β_ϵ of CH₂Cl₂ vapour in order to improve our knowledge of the intermolecular pair potential.