Electronic to vibrational energy transfer from I (5 2P1/2). I. HCl, HBr, and NO

Deactivation of I* (2P1/2) by HCl, HBr, and NO is directly observed to produce vibrationally excited states of the diatoms. The total deactivation rates are determined from either the decay of I* fluorescence or the rise of diatom fluorescence to be kEHCl= (4.46±0.77) ×102, kEHBr= (3.51±0.12) ×103, and kENO= (3.88±0.32) ×103 sec−1 torr−1. By comparing the intensity of I* fluorescence to that of the diatom it is found that the average number of vibrational quanta excited per deactivation of I* is 1.7±0.5, 2.3±0.5, and 3.4±0.7 for HCl, HBr, and NO, respectively. These findings are discussed in terms of recent models for E→V transfer.