Determination of Intermolecular-Potential Parameters from Induced Infrared Spectra: The Complex H2–Ar

Abstract

A Lennard‐Jones 12–6 potential has been used to calculate the induced infrared absorptionspectrum for the interaction of argon with molecular hydrogen. The results confirm the conclusion of Kudian, Welsh, and Watanabe that the observed spectrum is due in part to bound H2–Ar complexes. However, the calculations show that some changes are necessary in the tentative assignments which they made on empirical grounds. It is shown that the potential minimum Rm can be determined much more accurately from the spectrum than can the well depth ε. For H2–Ar, the combining rule, σ=½(σ1+σ2), is accurate to within at least 2%. The combining rule for well depth, ε=(ε1ε2)½, holds to within at least 10%.