CO2 LASER-INDUCED DESORPTION OF BENZOTRIFLUORIDE FROM NACL(100) AND C-FILM-NACL(100)

Resonant desorption of benzotrifluoride (BTF, C6H5CF3) was accomplished by tuning CO2-laser radiation into the symmetric C-F-stretch vibration on the substrates NaCl(100) and C-film-NaCl(100). Time-of-flight signals of desorbed molecules are of Maxwell-Boltzmann type without additional stream velocities. Translational temperatures (up to 3000 K) are always higher than the corresponding calculate maxima of substrate surface temperature. At benzotrifluoride coverages of ≈ 60 ML, desorption yield vs laser fluence plots give a power law for resonant desorption from NaCl(100), whereas for non-resonant desorption from C-film-NaCl(100) a linear relationship is observed. © 1990 Pergamon Press plc.