Vibrational energy transfer in the chemical energy regime using stimulated emission pumping

摘要

The dependence of vibrational energy transfer on vibrational excitation has been studied using the stimulated emission pumping technique to efficiently prepare a large range of specific vibrational states of the nitric oxide molecule in its ground electronic state. Laser-induced fluorescence was used to detect collisionally relaxed NO. The self-relaxation rate constants of NO(v $VGRT 1) were up to two hundred times larger than that of NO(v $EQ 1). Multiquantum relaxation was found to be important at high energy and was quantified at 3.8 eV. Theoretical explanations of our experimental results were attempted and it is shown that at vibrational energy up to approximately 3 eV the qualitative trends observed in these experiments such as: the mass effect and the linear dependence of the relaxation constant on v can be explained by Schwartz-Slawsky-Herzfeld theory. A simple explanation of the anomalously high NO self-relaxation rate is given. The large acceleration of the vibrational relaxation rate above 3.0 eV is coincident with the energetic onset of high energy (NO)$-2$/ isomer-complexes. More theoretical and experimental work is needed to explain the quantitative aspects of these observations.