Light-induced atomic desorption: Recent developments

Year: 2001

Authors: Mariotti E., Atutov S.N., Biancalana V., Bocci S., Burchianti A., Marinelli C., Nasyrov K.A., Pieragnoli B., Moi L.

Autors Affiliation: INFM-UdR Siena, Dipartimento di Fisica, Università di Siena, Via Banchi di Sotto 55, 53100 Siena, Italy

Abstract: Light induced atomic desorption (LIAD) is an impressive manifestation of a new class of phenomena involving alkali atoms, dielectric films and light. LIAD consists of a huge emission of alkali atoms (experimentally proved for sodium, potassium, rubidium and cesium) from siloxane films when illuminated by laser or ordinary light. Most of the experiments have been performed in glass cells suitably coated by a thin film (of the order of 10µm) either of poly – (dimethylsiloxane) (PDMS), a polymer, or of octamethylcyclotetrasiloxane (OCT), a crown molecule. LIAD is a combination of two processes: direct photo – desorption from the surface and diffusion within the siloxane layer. The photo – desorbed atoms are replaced by fresh atoms diffusing to the surface. Moreover, from the experimental data it comes out that the desorbing light increases atomic diffusion and hence the diffusion coefficient. To our knowledge this is the first time that such an effect is clearly observed, measured and discussed: LIAD represents a new class of photo-effects characterized by two simultaneous phenomena due to the light: surface desorption and fastened bulk diffusion.

Conference title:

KeyWords: Desorption; Dielectric films; Light emission; Polymers, Alkali atoms; Light induced atomic desorption (LIAD), Atomic physics
DOI: 10.1117/12.425139