Pulsed Laser‐Induced Thermal Desorption of Xenon

A 28 nm thick copper film with a temperature of 20 K, covered with approximately 100 monolayers of xenon is excited with a pulse from a XeCl laser. Time‐of‐flight signals of laser‐induced desorbed xenon are recorded with a quadrupole mass spectrometer. Simultaneously surface temperatures of the.copper film are measured with a pyroelectric calorimeter which serves as substrate for the copper film. The calorimetric temperatures are compared with translational temperatures derived from time‐of‐flight data. In the absence of any rotational or vibrational deexcitation channel, the maximum surface temperatures of the copper film are higher than the translational temperatures of desorbed xenon. In addition, non‐equilibrium desorption is reflected by a non‐Maxwellian line shape of the velocity distribution of desorbing xenon.