Electronically excited photodissociation and desorption of adsorbates: CH2I2 on Al2O3 and Ag surfaces

CH2I2 molecules adsorbed on Al2O3 and Ag surfaces are excited by a uv laser and the desorption behavior associated with photofragmentation is studied by time-of-flight mass spectrometry and x-ray photoemission and thermal desorption spectroscopies. The desorption yields as well as the mass and kinetic energy distributions are determined as functions of surface coverage and laser fluence. The results clearly reveal the characteristic electronic, thermal, and explosive desorption effects. © 1987 The American Physical Society.