Observation of an isotope effect in femtosecond laser-induced desorption of O 2 / Pd (111)

Femtosecond laser pulses can induce desorption of oxygen adsorbed in the molecular state on Pd(111) surfaces. In this study, the behavior of the 16 O 2 and 18 O 2 isotopic species is characterized for the saturated Pd(111) surface at a base temperature of 95 K. The 16 O 2 species is found to desorb with a yield 1.8±0.3 times greater than that of the 18 O 2 species. The implications of this finding for the desorption mechanism are discussed.