Molecular dynamics calculations of collision-induced absorption in a gas mixture of neon and krypton.

ABSTRACT

We continue the development of the in-house molecular dynamics software package SpaCIAL and test it for the computation of the collision-induced absorption coefficients for a neon (Ne) and krypton (Kr) gas mixture. An apodization procedure for the dipole autocorrelation function is implemented and tested. We also carry out a statistical study of the convergence rate with respect to ensemble size. The resulting absorption coefficients show a good accordance with quantum mechanical results. Comparison with laboratory measurements shows agreement within 10%-20% at T = 295 K. At T = 480 K, a larger difference of 40%-80% is observed, which can presumably be explained by experimental uncertainties. For the study, an empirical (Barker, Fisher, and Watts) interaction-potential [Mol. Phys. 21, 657 (1971)] for Ne-Kr has been developed. Ab initio {coupled cluster with singles and doubles (triples) [CCSD(T)]} potentials for Ne-Ne, Kr-Kr, and Ne-Kr have been computed, as well as the CCSD(T) interaction-induced Ne-Kr dipole moment curve.