Infrared radiative decay constants for the vibrational levels of CO (a 3Π)

The decay of the CO (a 3Π,v′=0–3) levels have been studied in a flowing-afterglow apparatus. The vibrational distribution was monitored by observing the CO (a 3Π→X 1Σ+) emission intensity. The results were interpreted to obtain 52.5, 77, and 178 sec−1 for the infrared radiative decay constants for the v′=1, 2, and 3 vibrational levels of CO (a 3Π). The data also establish that the upper limit to the rate constant for vibrational relaxation of CO (a) by collision with He is ?6×10−17 cm3 molecule−1 sec−1, corresponding to a collision probability of ?1.5×10−7.