Thermal desorption spectra of acetone on Si(100) were measured using a temperature programmed desorption (TPD) technique. Acetone molecules condensed on a Si(100) at 95 K desorbed at 133 K. The peak profile indicated a zeroth-order desorption mechanism. The desorption energy was estimated to be 47.6 ± 4 kJ/mol. Dissociation and desorption of the acetone molecules condensed on the surface by 193 nm pulsed laser irradiation were investigated with a quadrupole mass spectrometer using a time-of-flight technique. When high fluence laser pulses of 363 mJ/cm2 were irradiated to a thick layer of acetone formed by an exposure of 1500 L, hyperthermal acetone molecules of about 2 eV were observed desorbing from the surface. Acetyl and methyl radicals formed by dissociation were also vaporized simultaneously. Thermal dissociation of acetone leading to 2CH3 and CO as products occurred slowly after the laser irradiation. These dissociation processes are different from those in the gas phase.
- Laser induced thermal desorption (LITD)
- Silicon carbide
- Solid-gas interfaces
- Surface photochemistry
- Thermal desorption