Journal of Chemical Physics, Vol.100, No.7, 4884-4893, 1994
Predissociation in the (A)over-Tilde (2)A’ State of Hnf (Dnf) - NH (Nd) Photofragment Excitation Spectroscopy
Photofragment excitation spectra of room-temperature HNF and DNF have been measured by monitoring laser fluorescence of the NH(X 3SIGMA-) and ND(X 3SIGMA) fragments, respectively. These fragments were observed upon the excitation of the following parent molecule A 2A’ vibrational levels : HNF (0,upsilon2’,0), with upsilon2’ = 3-6; and DNF (0,upsilon2’,0), with upsilon2’ = 5-7, and (0,upsilon2’,1), with upsilon2’ = 3 and 4. With the exception of the highest levels, the photofragment excitation spectra were found to have complicated structures which were drastically different and more complicated than the K structure in the parent molecule absorption and fluorescence excitation spectra. The internal energy content of the fragments was also measured. For the lower HNF (DNF) levels the fragments possess very little rotational energy; for higher parent molecule levels the fragment rotational energy is correlated with the parent energy. The fragmentation of excited HNF (DNF) is complicated by the fact that there are three close-lying possible dissociation channels, to NH(X 3SIGMA-) +F(2P), NF(X 3SIGMA-)+H(2S), and HF(X 1SIGMA+)+N(2D). These results on the photofragmentation of excited HNF (DNF) and other observations from this laboratory on the parent laser fluorescence spectrum and measured decay lifetimes are discussed.
Keywords:MAGNETIC-ROTATION SPECTROSCOPY;LAMBDA-DOUBLET SELECTIVITY;LASER-INDUCED FLUORESCENCE;EXPANSION-COOLED NO2;VISIBLE ABSORPTION;ELECTRONIC STATE;INDUCED GRATINGS;BOND-BREAKING;SPIN-DOUBLET;FREE JETS