Correlation times for liquid CH2Cl2

The overall consistency of experimentally available correlation times for liquid CH2Cl2 is tested with the aid of a new computer simulation at 293K lbar, using a 5 × 5 Lennard-Jones atom-atom potential with charges situated at the atomic sites. The various N.M.R. correlation times and the dielectric relaxation time are satisfactorily in line with the computer simulation. The infra-red correlation time reported by van Konynenberg and Steele is consistent with the simulation, but those reported by Rothschild are over 100 too short. The correlation time from depolarised Rayleigh scattering is over 3 times longer than the simulation result, and the neutron-scattering correlation time of Brier and Perry is about 100. shorter. The computer simulation reproduces the far infra-red spectrum of liquid CH2Cl2 fairly well and is therefore considered to be reliable.A coordinated project, such as the EMLG Delta Project is needed to improve the overall consistency of these basic features of liquid phase molecular dynamics, exemplified by liquid CH2Cl2.