Contribution from dimers to the collision-induced absorption spectra in an Ar–Kr gas mixture

We have developed an empirical Barker, Fisher and Watts (BFW) interatomic potential for the Ar–Kr pair along with a dipole moment computed from first principles using Møller–Plesset perturbation theory to second order (MP2). Using these results, we performed molecular dynamics calculations to compute the Ar–Kr collision induced absorption (CIA) spectrum at different temperatures. By comparing them to other calculations using a two body interaction treated with quantum mechanics, we have shown that the difference is due to the dimer's contribution which grows in importance as the temperature is lowered.