COMPETING PHOTODISSOCIATION PATHWAYS FOR PHYSISORBED O-2 GRAPHITE INVESTIGATED USING AR SPACER LAYERS/

Citation
Cm. Friedrich et al., COMPETING PHOTODISSOCIATION PATHWAYS FOR PHYSISORBED O-2 GRAPHITE INVESTIGATED USING AR SPACER LAYERS/, Chemical physics letters, 247(4-6), 1995, pp. 348-354
Citations number
20
Categorie Soggetti
Physics, Atomic, Molecular & Chemical
Journal title
ISSN journal
00092614
Volume
247
Issue
4-6
Year of publication
1995
Pages
348 - 354
Database
ISI
SICI code
0009-2614(1995)247:4-6<348:CPPFPO>2.0.ZU;2-9
Abstract
We have studied photon stimulated ion desorption from O-2 physisorbed on graphite, using synchrotron radiation in the energy range 16-40 eV, Ar spacer layers were employed in order to distinguish between direct and indirect (photoelectron driven) dissociation channels, specifical ly, (i) direct dipolar dissociation, (ii) direct dissociative ionizati on, (iii) photoelectron driven dissociative attachment and (iv) photoe lectron driven dipolar dissociation. We find that the O- yield is main ly due to direct dipolar dissociation, while for O+ direct dipolar dis sociation and both direct and indirect dissociative ionization are ide ntified. The Ar layer reduces the image potential arising from the gra phite substrate. Some dissociation pathways in the energy region 24-27 eV are enhanced for O-2/graphite compared with the gas phase.