State-resolved femtosecond two-pulse correlation measurements of NO photodesorption from Pt(1 1 1)

State-resolved two-pulse correlation measurement is useful to study the time scale and mechanism of photo-induced desorption as well as electronic structures of admolecules before desorption. In photodesorption of nitric oxide molecules from Pt(1 1 1) at 250 K induced by 80 fs, 620 nm laser pulses, the yields and translational temperatures reached a maximum at zero delay time. In contrast, the rotational temperature of Ω=3/2 molecules reached a maximum at a delay time of ±1 ps, while that of Ω=1/2 molecules was enhanced at around zero delay. In addition, the ratio of total yields of Ω=1/2 molecules to that of Ω=3/2 molecules increased at short delay times. All of these results can be explained by the model of rotational heating, including spin–orbit (SO) coupling, where the difference in the correlation time was found to be due to the SO structure in the adsorbed phase.