Rotational energy transfer in Na*2 (<i>A</i> Σ) colliding with Xe, Kr, Ar, Ne, He, H2, CH4, and N2: Experiment and fitting laws

Abstract

Using the method of laser-induced fluorescence, we have measured level to level rate constants for rotational energy transfer (RET) in Na*2 colliding with Xe, Kr, Ar, Ne, He, H2, N2, and CH4. For each target gas we varied the initial rotational quantum number ji over a wide range, typically 4–100, and measured approximately 60 rate constants with an average error of between 6% and 9%. The resulting base of 479 rate constants is used to test several recently proposed fitting laws. The energy corrected sudden scaling law of DePristo et al., when combined with the assumption of a power gap law for the basis rate constants kl→0, fit with only 3 parameters all of the data for a given target gas with 7%–12% average percentage deviation. Our statistical power gap law worked well and was generally the best law for those data sets with only one value of ji. The worst fits in all cases considered here were those using the exponential gap law of surprisal theory.