Selective desorption from the binary coadsorbate C 2H 6CH 3FNaCl by resonant vibrational excitation with laser infrared radiation

Abstract

After measuring the linear infrared absorption spectrum of the coadsorbate, selective desorption of CH 3F from the binary coadsorbate C 2H 6CH 3FNaCl under ultrahigh vacuum conditions at 12o K stimulated by resonant CO 2 laser pulses of small fluence ∼ 0.1 J·cm t−2 has been carried out. No desorption of ethane, which is slightly more volatile, but has no significant infrared absorption at the laser frequency, was observed. The primary activation step is the resonant multiphoton excitation of the most intense internal CH 3FNaCl adsorbate vibration, the CF stretching mode ν 3. The substance separation seems to indicate high localisation of the activation in this desorption and could be of interest for applications.