Vj. Erkkila et al., PHOTOCHEMISTRY OF O-2 ON AG(110) USING PICOSECOND ULTRAVIOLET-LASER PULSES, Journal of vacuum science & technology. A. Vacuum, surfaces, and films, 14(3), 1996, pp. 1552-1556
Citations number
13
Categorie Soggetti
Physics, Applied","Materials Science, Coatings & Films
Surface second-harmonic generation (SHG) was used to study the photoch
emical reaction of O-2 with Ag(110) using similar to 6 ps laser pulses
. A clean well-ordered Ag(110) surface produces a strong SHG signal at
580 nm. The SHG signal measured in real time during O-2 exposure is s
ensitive to submonolayer coverages of O-2 and to the subsequent exposu
re of this system to picosecond ultraviolet laser pulses. Upon O-2 ads
orption at 130 and 200 K, the signal decreases by more than a factor o
f 2 at saturation coverage. Langmuir adsorption kinetics are used to f
it the O-2 dosage curves relating the decrease in SHG intensity to the
oxygen coverage. Subsequent exposure of the surface dosed at 130 K to
290 nm light of the same pulse width also produces a change in the se
cond-harmonic response. Combined with surface SHG temperature programm
ed desorption measurements, these results are correlated to the photoc
hemical reaction taking place on the surface in which chemisorbed O-2
photodissociates and photodesorbs. The results of the surface photoche
mical reaction initiated by picosecond UV pulses are compared to those
previously studied using continuous wave radiation and are found to h
ave similar overall behavior while possibly showing some new features.
(C) 1996 American Vacuum Society.