Semiclassical analysis of vibrational energy transfer in HF–HF and isotopic systems. I. V-T/R and V-V rate constants for the lowest transitions in HF–HF

Semiclassical calculations of the V-R/T and V-V rate constants among the lowest vibrational transitions in the HF–HF collisional system in the temperature range 200–3500 K are presented. The interaction potentials used are fits of the functional form used successfully in earlier work to recent large scale ab initio calculations of the energy surface of the hydrogen fluoride dimer in the framework of coupled pair functional and averaged coupled pair functional methods. The semiclassical results are in good agreement with experimental data and differ advantageously from the very recent classical trajectory cross-correlation calculations, which are based on potential fits to the same ab initio points as used in the present paper.