Light-induced ejection of calcium atoms from polymer surfaces
Dipartimento di Fisica “E. Fermi”, Largo Pontecorvo, 3, 56126 Pisa, Italy
Corresponding author: a email@example.com
Revised: 19 September 2008
Published online: 28 November 2008
Laser-induced fluorescence (LIF) of calcium atoms at room temperature has been observed in a polydimethylsiloxane (PDMS) coated cell when the walls are illuminated with non resonant visible light. Ca atomic density in the gas phase, monitored by the LIF, is much higher than normal room-temperature vapour pressure of calcium. In past years photon-stimulated desorption (PSD) was observed for several alkali metals that adsorbed to solid films of PDMS polymers. High yields of photo-desorbed atoms (and molecules in the case of sodium) can be induced, at room temperature and below, by weak intensity radiation. The desorption is characterised by a frequency threshold, whereas any power threshold is undetectable. The calcium photo-ejection is characterised both by a frequency threshold (about 18 500 cm-1) and by an observable power threshold (whose value becomes lower when the photo-ejecting light wavelength decreases).
PACS: 68.43.Tj – Photon stimulated desorption
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2008