Vibronic effects on electron impact excitations of CO_2 studied by angle-resolved EELS

摘要

Detailed information on photon- and electron-impact excitation of CO_2 has been attracting broad interest from a diverse range of studies [1]. One of the most thoroughly investigated excitation processes of CO_2 is the valence-shell electronic excitation in the ultraviolet region. In spite of tremendous experimental and theoretical efforts, however, the interpretation of some spectral features has remained controversial. A possible cause of the difficulty in the interpretation may be related to effects of coupling between electronic and nuclear motions, i.e. vibronic effects. Such effects may substantially affect electronic transition probabilities and thus make it difficult to interpret experimental observations. In this contribution, we report our recent electron-energy-loss spectroscopy (EELS) study of vibronic effects on valence-shell electronic excitations in CO_2 [2].