Calculated spectra for the N2-Ar van der Waals complex

Abstract

Calculations are presented that estimate the energies of all the truly bound states of the N₂-Ar van der Waals complex using a semi-empirical potential-energy surface. An effective dipole surface is constructed by comparison with the infrared spectra of McKellar. These spectra are reproduced by convoluting the 30 000 strongest transitions with suitable temperature- and pressure-dependent line profiles. These synthetic spectra reproduce the observed experimental features, supporting and extending McKellar's assignments. Some of the peaks are shifted to higher frequency, suggesting that the bending potential is slightly too stiff. The corresponding ‘pure’ (far-infrared) spectra of the van der Waals complex are also synthesized. These do not show the low-frequency features seen in the infrared spectra.