I∗ production from n-alkyl iodides at 222 nm

The dynamics of I∗ (2P12) production in a series of n-alkyl iodides at 222 run have been investigated. Data are analyzed using a simple classical impulsive model. At this excitation wavelength, 1 (2P32) originates from a curve-crossing between the 3Q0 and 1Q1 surfaces and the probability of crossing for all the iodides has been derived. Since the I∗ quantum yield is found to decrease, the probability of crossing increases as a function of the alkyl radical size, which is also consistent with the classical model.