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Titolo:
Hydrogen adsorption and desorption on silicon revisited
Autore:
Hilf, MF; Brenig, W;
Indirizzi:
Tech Univ Munich, Dept Phys, D-85747 Garching, Germany Tech Univ Munich Garching Germany D-85747 hys, D-85747 Garching, Germany
Titolo Testata:
JOURNAL OF CHEMICAL PHYSICS
fascicolo: 7, volume: 112, anno: 2000,
pagine: 3113 - 3116
SICI:
0021-9606(20000215)112:7<3113:HAADOS>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
NUMERICALLY STABLE SOLUTION; COUPLED-CHANNEL EQUATIONS; INITIO MOLECULAR-DYNAMICS; PHONON-ASSISTED STICKING; DETAILED BALANCE; H-2 DESORPTION; SURFACE; SI(100); KINETICS; SI(111)-(7X7);
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
34
Recensione:
Indirizzi per estratti:
Indirizzo: Hilf, MF Tech Univ Munich, Dept Phys, D-85747 Garching, Germany Tech Univ Munich Garching Germany D-85747 747 Garching, Germany
Citazione:
M.F. Hilf e W. Brenig, "Hydrogen adsorption and desorption on silicon revisited", J CHEM PHYS, 112(7), 2000, pp. 3113-3116

Abstract

Recent molecular beam data on the energy dependence of sticking coefficients for dissociative adsorption of hydrogen molecules on silicon are analyzed in terms of the five dimensional (5D) quantum reaction dynamics used before to describe data on sticking as a function of surface temperature and onstate resolved desorption. The sticking coefficient of the 5D model depended strongly on the energy of surface phonons but weakly on the kinetic energy of the incoming H-2 molecules. In a recent molecular beam experiment thelatter dependence was measured directly and found to be substantially stronger than concluded from the earlier data. These results have important consequences for the energy and angular distribution of desorbing particles: If the parameters of the 5D model are adjusted so as to describe the new data, it predicts a mean normal kinetic energy of desorbing particles which isnow about twice the thermal value. This prediction is rather model independent and can be derived almost directly from the measured data by invoking "detailed balance. '' This new increased normal mean energy then is closer to ab initio generalized gradient approximation (GGA) slab calculations predicting about three times the thermal value. The increased kinetic energy also leads to a more forward-peaked angular distribution proportional to (costheta)(11 to 12) instead of proportional to(cos theta)(3 to 4). (C) 2000 American Institute of Physics. [S0021-9606(00)70707-0].

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Documento generato il 30/11/20 alle ore 10:10:40