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Titolo: REACTION DYNAMICS OF MOLECULARHYDROGEN ON SILICON SURFACES
Autore: BRATU P; BRENIG W; GROSS A; HARTMANN M; HOFER U; KRATZER P; RUSS R;
 Indirizzi:
 MAX PLANCK INST QUANTUM OPT D85740 GARCHING GERMANY TECH UNIV MUNICH,DEPT PHYS D85747 GARCHING GERMANY MAX PLANCK GESELL,FRITZ HABER INST D14195 BERLIN GERMANY TECH UNIV DENMARK,CTR ATOM SCALE MAT PHYS DK2800 LYNGBY DENMARK TECH UNIV DENMARK,DEPT PHYS DK2800 LYNGBY DENMARK
 Titolo Testata:
 Physical review. B, Condensed matter
fascicolo: 8,
volume: 54,
anno: 1996,
pagine: 5978  5991
 SICI:
 01631829(1996)54:8<5978:RDOMOS>2.0.ZU;2S
 Fonte:
 ISI
 Lingua:
 ENG
 Soggetto:
 NUMERICALLY STABLE SOLUTION; COUPLEDCHANNEL EQUATIONS; SCANNING TUNNELING MICROSCOPY; INTERNALSTATE DISTRIBUTIONS; PHONONASSISTED STICKING; PIBONDED DIMERS; H2 DESORPTION; SI(100)2X1 SURFACE; ATOMICHYDROGEN; RECOMBINATIVE DESORPTION;
 Tipo documento:
 Article
 Natura:
 Periodico
 Settore Disciplinare:
 Science Citation Index Expanded
 Citazioni:
 86
 Recensione:
 Indirizzi per estratti:



 Citazione:
 P. Bratu et al., "REACTION DYNAMICS OF MOLECULARHYDROGEN ON SILICON SURFACES", Physical review. B, Condensed matter, 54(8), 1996, pp. 59785991
Abstract
Experimental and theoretical results on the dynamics of dissociative adsorption and recombinative desorption of hydrogen on silicon are presented. Using optical secondharmonic generation, extremely small sticking probabilities in the range 10(9)10(5) could be measured for H2 and D2 on Si(111)7X7 and Si(100)2X1. Strong phononassisted sticking was observed for gases at 300 K and surface temperatures between 550K and 1050 K. The absolute values as well as the temperature variation of the adsorption and desorption rates show surprisingly little isotope effect, and they differ only little between the two surfaces. These results indicate that tunneling, molecular vibrations, and the structural details of the surface play only a minor role for the adsorptiondynamics. Instead, they appear to be governed by the localized HSi bonding and SiSi lattice vibrations. Theoretically, an effective fivedimensional model is presented taking lattice distortion, corrugation,and molecular vibrations into account within the framework of coupledchannel calculations. While the temperature dependence of the sticking is dominated by lattice distortion, the main effect of corrugation is a reduction of the preexponential factor by about one order of magnitude per lateral degree of freedom. Molecular vibrations have practically no effect on the adsorption/desorption dynamics itself, but lead to vibrational heating in desorption with a strong isotope effect. Ab initio calculations for the H2 interaction With the dimers of Si(100)2X1 show properties of the potential surface in qualitative agreement with the model, but its dynamics differs quantitatively from the experimental results.
ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 16:42:38