EXPERIMENTAL MEASUREMENTS OF STATE-RESOLVED, ROTATIONALLY INELASTIC ENERGY-TRANSFER

great deal of experimental effort has been put toward measurements of integral and differential, state-to-state cross-sections for rotationally inelastic energy transfer. Throughout the years measurements in thermal gas cells, and in crossed molecular beams, have been performed at increasingly impressive levels of quantum state detail. Because the term 'rotational energy transfer' can include collisional interchange among nuclear rotational states, magnetic sublevels, electron spin and orbital quantum levels, and vibrational angular momentum states, and can also include rotation-translation/vibration energy transfer, the field is an expansive one. In this review an array of experimental studies is encapsulated, including discussion of quantum-state propensities, their known or speculative physical origins, and the success or failure of simple energy transfer models. Discussion of progress toward the development of accurate, intermolecular potential energy surfaces, and the results of classical or quantum scattering calculations, accompanies the overview of experimental work.