Probing the alignment of NO(X ~2#PI#) by [2 + 1] resonance-enhanced multiphoton ionization via the C ~2#PI# state: A test of semiclassical theory in 355 nm photodissociation of NO_2

摘要

A theoretical method to analyze the two- and three-dimensional imaging data of photofragments with polarized angular momentum was tested by comparing with the experimental data on NO from 355 nm photodissociation of NO_2. The alignment of NO(X ~2#PI#) was detected by [2 + 1] resonance-enhanced multiphoton ionization via the C ~2#PI# state. The data were analyzed by assuming the #mu#-#nu#-J triple vector correlation described by semiclassical multipole moments in the velocity-fixed frame. The geometrical factors for the two-photon absorption were derived rigorously for the intermediate coupling between Hund's cases (a) and (b). It was also shown, however, that the geometrical factors for high J are independent of the coupling case and can be approximated by simple formulas. Excellent agreement between the simulation and the experimental data proved the validity of the semiclassical treatment.