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Titolo:
THEORETICAL-STUDY OF THE MECHANISM OF RECOMBINATIVE HYDROGEN DESORPTION FROM THE MONOHYDRIDE PHASE OF SI(100) - THE ROLE OF DEFECT MIGRATION
Autore:
NACHTIGALL P; JORDAN KD; SOSA C;
Indirizzi:
UNIV PITTSBURGH,DEPT CHEM PITTSBURGH PA 15260 UNIV PITTSBURGH,DEPT CHEM PITTSBURGH PA 15260 CRAY RES INC EAGAN MN 55121
Titolo Testata:
The Journal of chemical physics
fascicolo: 9, volume: 101, anno: 1994,
pagine: 8073 - 8081
SICI:
0021-9606(1994)101:9<8073:TOTMOR>2.0.ZU;2-U
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR-ORBITAL METHODS; VALENCE BASIS-SETS; PI-BONDED DIMERS; CORRELATION ENERGIES; 1ST-ROW ELEMENTS; H-2 DESORPTION; SURFACE; KINETICS; DIFFUSION; APPROXIMATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
45
Recensione:
Indirizzi per estratti:
Citazione:
P. Nachtigall et al., "THEORETICAL-STUDY OF THE MECHANISM OF RECOMBINATIVE HYDROGEN DESORPTION FROM THE MONOHYDRIDE PHASE OF SI(100) - THE ROLE OF DEFECT MIGRATION", The Journal of chemical physics, 101(9), 1994, pp. 8073-8081

Abstract

Density functional theory with nonlocal corrections is used together with cluster models to examine various pathways for H-2 desorption from the Si(100)2X1 surface. The barrier calculated for direct desorptionof H-2 from the doubly-occupied dimer is appreciably larger than the experimentally observed activation energy at submonolayer coverages. We propose a mechanism in which surface defects are converted into dihydride (SiH2) species from which H-2 desorption occurs. The barrier calculated for this process (57 kcal/mol) is in excellent agreement with the measured activation energy. The barrier for defect migration is predicted to be only 14 kcal/mol, so that a single defect can account for the desorption of H, from a large number of monohydride sites. Single-point calculations for several of the optimized structures are carried out using the quadratic configuration interaction (QCI) method. Thereaction energies and barrier heights calculated with the QCI and density functional theory (DFT) methods are in excellent agreement.

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Documento generato il 02/12/20 alle ore 17:55:18