Time-sliced ion imaging study of I2 and I2+ photolysis at 532 nm

Abstract

Photodissociation of I₂ and I₂⁺ at 532.10 nm was studied using VUV photoionization/time-sliced velocity map imaging. The dissociation energies D₀ of I₂(X ¹Σ⁺_g) and I₂⁺(X ²Π_1/2g) were found to be 12 416 ± 48 and 16 439 ± 48 cm⁻¹, respectively. Absorption of 532.10 nm mainly corresponds to the excitation of I₂(X ¹Σ⁺_g) to the ¹Π(1_u) and/or A³Π(1_u) states, and the excitation of I₂⁺(X ²Π_1/2g) to the A²Π_1/2u state, with a small fraction to the A²Π_3/2u and ⁴Σ⁺_u states. A method for accurate calibration of magnification factor of ion imaging system was presented. The improvement of energy resolution for large ionization volume experiments, like the crossed molecular beam and one-photon VUV photoionization experiments, was discussed.