COLLISIONAL EFFECTS IN THE IR MULTIPHOTON ABSORPTION AND DISSOCIATIONOF SI2F6

IR multiphoton absorption (MPA) and dissociation (MPD) of Si2F6 in Ar were investigated. For the 10R(26) line (979.7 cm(-1)) of the CO2 lase r, the average number of photons absorbed and the MPD yield were obtai ned for different laser fluences and buffer gas pressures. The fractio n of excited molecules was as high as 70%. The MPD probability was fou nd to be heavily suppressed when more than 5 Torr of Ar buffer gas was added, indicating that vibrational deactivation is predominant over M PA increase with pressure.