Energy Transfer in the 2(u) ((1)D(2)) Ion-Pair State of I(2) by Inelastic Collisions with Noble Gas Atoms

[Image: see text] We investigated the energy transfer in the 2(u) ((1)D(2)) ion-pair state of I(2) by collision with noble gas atoms, Ar, Kr, and Xe, using an optical–optical double resonance/fluorescence detection technique. By analyzing the temporal profiles of the emission from the laser-excited 2(u) ((1)D(2)) state at various noble gas pressures, the quenching rate constants [Image: see text] were determined to be (4.55 ± 0.42) × 10(–10), (4.23 ± 0.11) × 10(–10), and (6.83 ± 0.16) × 10(–10) cm(3) molecule(–1) s(–1) for quenching by Ar, Kr, and Xe, respectively. The 2(g) ((1)D(2)) ion-pair state, lying in the vicinity of the 2(u) ((1)D(2)) state, was identified as a destination state by collision with Ar and Kr. Collision with Xe provided a new reactive pathway forming the excimer XeI(B). The rate constants were determined to be [Image: see text] = (9.61 ± 0.63) × 10(–11) cm(3) molecule(–1) s(–1) and [Image: see text] = (4.87 ± 0.34) × 10(–11) cm(3) molecule(–1) s(–1) for the formation of the 2(g) ((1)D(2)) state by collision with Ar and Kr, respectively, and [Image: see text] = (6.55 ± 0.19) × 10(–11) cm(3) molecule(–1) s(–1) for the formation of XeI(B). The collisional cross sections calculated from the quenching rate constants were considerably larger than the molecular size, owing to the harpoon mechanism.