A versatile technique employing pulsed quadrupole ion storage mass spectrometry and a low power CW CO2 laser for the study of slow infrared multiphoton dissociation of gaseous ions under collision-free conditions is described. Multiphoton dissociation of gaseous ions derived from isopropanol.
The large extent of dissociation observed with low laser flucnce is indicative of both the rapid collisionally-induced migration of ions to the centre of the QUISTOR (and hence the laser beam) and also the predominance of multiphoton absorption over radiative and collisional deactivation processes in the time and pressure domains employed here.