Experimental and theoretical photofragmentation dynamics of rovibronic-magnetic state-selected ND₃

Results of experimental and theoretical studies of the rovibrationally state-selected photodissociation dynamics of ND₃ at 193.3 nm are reported. ND₃ molecules in the antisymmetric inversion doublet level were state-selectively focused, using an electrostatic hexapole, into several rovibronic-magnetic states. The velocity distributions of the D atom for photofragmentation of ND₃ in each of these fully selected states were measured using Doppler spectroscopy. The resulting Doppler profiles were fitted by comparison with profiles calculated using a fully quantum mechanical photofragmentation theory. At the high photon energies considered, the total photofragmentation cross-section was found to be relatively insensitive to the initial rotational energy level. Analysis of the fully state-selected differential photofragmentation cross-sections in terms of R-, Q- and P-branch scattering waves allowed the matrix elements of the transition dipole operator to be determined. These matrix elements confirm a parallel transition with the D atom recoiling primarily along the C₃ axis for the photodissociation of ND₃ at 193.3 nm.