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

Photodissociation of I-2 and I-2(+) at 532.10 nm was studied using VUV photoionization/ time- sliced velocity map imaging. The dissociation energies D-0 of I-2( X (1)Sigma(+)(g)) and I-2(+)( X (II1/ 2g)-I-2) 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 I-2( X (1) Sigma(+)(g)) to the (II)-I-1(1(u)) and/ or A(3) II(1(u)) states, and the excitation of I-2(+)( X (II1/2g)-I-2) to the A(2) II1/2u state, with a small fraction to the A(2) II3/2u and (4)Sigma(+)(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.