THE WAVELENGTH DEPENDENCE OF TERT-BUTYL NITRITE SURFACE PHOTOCHEMISTRY

The surface photochemistry of tert-butyl nitrite adsorbed on Ag(lll) w as investigated at 532 and 266 nm. The desorbing molecules were detect ed in time of flight (TOF) mode by a mass spectrometer. Irradiation of the adsorbates leads to desorption of NO at both wavelengths. At thes e wavelengths caging and bimodal WO TOF distributions, consisting of a hyperthermal and a thermal component, are observed, At 532 nm dissoci ation is governed by a direct excitation with a cross section of 2 x 1 0(-21) cm(2). The observed TOF distributions at 266 nm are very simila r to the 355 nm results, although generally higher translational energ ies and cross section values (2 x 10(-19) cm2) were measured. At 266 n m dissociation proceeds via a direct excitation. The results are consi stent with an excitation into the S-1 state at 355 nm and excitation i nto the S-2 state at 266 nm.