Direct observation of rotational cooling in thermal desorption: No/Pd(111)

The rotational energy distribution of nitric oxide desorbed from a Pd(111) surface has been determined directly at high surface temperature by means of laser heating of the substrate. For a surface temperature of Ts = 1100 ± 100 K, the rotational energy distribution of the desorbed NO could be described as thermal, but with a significantly lower temperature of Tr = 640 ± 40 K. © 1990.