Long-range collisional energy transfer between charge-transfer ,,ion-pair…states of I2, induced by H2O and I2,,X…

摘要

Long-range -resonantenergy transfer, between g/u charge-transfer states of molecular iodine i.e.,f0g+-3P0→F0u +-3P0and E0g +-3P2→D0u +-3P2-, induced by collisions with H2O and I2-Xvia multipole coupling, has been observed. Large rate constants, up to 5-10-9 molecules-1 cm3 s-1,for collisional transfer between a range of vibrational levels of the f0g+-3P0and F0u +-3P0ion-pair states of I2, by H2O, are reported. Some previously reported studies on E0g +-3P2→D0u +-3P2and f0g +-3P0→F0u+-3P0collisional transfer, induced by I2-X, have been repeated and revised rate data are presented; the range of initially excited vibrational states studied has also been extended. Much smaller rate constants for quenching by I2-X, compared to H2O, are found and it is proposed that H2O desorbed from the walls of the sample cell could have significantly affected much larger rate data previously reported in the literature. For both collision partners, a model is proposed in which long-range, near-resonant interactions can occur when there is close matching of the change in energy in the ion-pair states with the change in energy that accompanies the rotational transition undergone by the collision partner.