STATE-SPECIFIC PHOTOFRAGMENT YIELD SPECTROSCOPY OF JET-COOLED METHYL NITRITE

We obtained state-specific photofragment yield (PHOFRY) spectra of jet -cooled CH3ONO in the S1 <-- S0 absorption system by monitoring select ed rotational levels in NO v = 0, 1 and 2. The spectra exhibit bands w hich are assigned to both the syn- and anti-rotamers with origins at 3 80 nm and 388 nm, respectively. All the bands are broad (500-800 cm-1) suggesting that the dissociation lifetimes are shorter than those obt ained in dynamical calculations on model potential energy surfaces. Th e widths do not depend on the monitored NO rotational level. The resul ts support a mechanism where nonadiabatic vibrational predissociation is preferred.