Internal state distribution of molecular hydrogen isotopes desorbing from clean and modified Ni(110) surfaces
✍ Scribed by A. Winkler; G. Eilmsteiner; R. Novak
- Publisher
- Elsevier Science
- Year
- 1994
- Tongue
- English
- Weight
- 556 KB
- Volume
- 226
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Rotational and vibrational state distributions for Hz, HD and Ds desorbing from clean and sulfur covered Ni ( 110) surfaces have been measured using resonantly enhanced multiphoton ionization (REMPI). For the clean surface the mean rotational energy of desorbing Hz and Ds is slightly smaller than kT,, with the lowest value of 0.75 kT, for HD. On the sulfur-covered surface a nearly thermalized rotational state distribution is observed for all three isotopes. The population of the first excited vibrational state is enhanced by a factor of two for Ha and Dz desorbing from the clean surface, compared with a Boltzmann distribution. With increasing sulfur coverage the population P( nr) increases up to a sixfold overpopulation at &=O.S ML. No orientational effects with respect to helicopter or cartwheel modes in the desorption flux of hydrogen could be observed.