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Title: Reactivity of aluminum cluster anions with ammonia: Selective etching of Al{sub 11}{sup -} and Al{sub 12}{sup -}

Abstract

Reactivity of aluminum cluster anions toward ammonia was studied via mass spectrometry. Highly selective etching of Al{sub 11}{sup -} and Al{sub 12}{sup -} was observed at low concentrations of ammonia. However, at sufficiently high concentrations of ammonia, all other sizes of aluminum cluster anions, except for Al{sub 13}{sup -}, were also observed to deplete. The disappearance of Al{sub 11}{sup -} and Al{sub 12}{sup -} was accompanied by concurrent production of Al{sub 11}NH{sub 3}{sup -} and Al{sub 12}NH{sub 3}{sup -} species, respectively. Theoretical simulations of the photoelectron spectrum of Al{sub 11}NH{sub 3}{sup -} showed conclusively that its ammonia moiety is chemisorbed without dissociation, although in the case of Al{sub 12}NH{sub 3}{sup -}, dissociation of the ammonia moiety could not be excluded. Moreover, since differences in calculated Al{sub n}{sup -}+NH{sub 3} (n=9-12) reaction energies were not able to explain the observed selective etching of Al{sub 11}{sup -} and Al{sub 12}{sup -}, we concluded that thermodynamics plays only a minor role in determining the observed reactivity pattern, and that kinetics is the more influential factor. In particular, the conversion from the physisorbed Al{sub n}{sup -}(NH{sub 3}) to chemisorbed Al{sub n}NH{sub 3}{sup -} species is proposed as the likely rate-limiting step.

Authors:
; ; ;  [1];  [2];  [3];  [4]
  1. Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States)
  2. Institut fuer Anorganische Chemie, Karlsruhe Universitaet, Karlsruhe 76128 (Germany)
  3. Departamento de Ciencias Exactas y Tecnologia, Centro Universitario de Los Lagos, Universidad de Guadalajara, Jalisco 47460 (Mexico)
  4. Departamento de Materia Condensada y Criogenia, Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Coyoacan 04510, Distrito Federal (Mexico)
Publication Date:
OSTI Identifier:
21559803
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 131; Journal Issue: 18; Other Information: DOI: 10.1063/1.3256236; (c) 2009 American Institute of Physics
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 74 ATOMIC AND MOLECULAR PHYSICS; ADSORPTION; ALUMINIUM; ALUMINIUM COMPOUNDS; AMMONIA; ANIONS; ATOMIC CLUSTERS; CHEMICAL ANALYSIS; CHEMISORPTION; DISSOCIATION; ETCHING; ION-MOLECULE COLLISIONS; MASS SPECTROSCOPY; MOLECULAR CLUSTERS; PHOTOELECTRON SPECTROSCOPY; REACTION KINETICS; REACTIVITY; SIMULATION; THERMODYNAMICS; CHARGED PARTICLES; CHEMICAL REACTIONS; COLLISIONS; ELECTRON SPECTROSCOPY; ELEMENTS; HYDRIDES; HYDROGEN COMPOUNDS; ION COLLISIONS; IONS; KINETICS; METALS; MOLECULE COLLISIONS; NITROGEN COMPOUNDS; NITROGEN HYDRIDES; SEPARATION PROCESSES; SORPTION; SPECTROSCOPY; SURFACE FINISHING

Citation Formats

Grubisic, Andrej, Li Xiang, Gantefoer, Gerd, Bowen, Kit H., Schnoeckel, Hansgeorg, Tenorio, Francisco J., and Martinez, Ana. Reactivity of aluminum cluster anions with ammonia: Selective etching of Al{sub 11}{sup -} and Al{sub 12}{sup -}. United States: N. p., 2009. Web. doi:10.1063/1.3256236.
Grubisic, Andrej, Li Xiang, Gantefoer, Gerd, Bowen, Kit H., Schnoeckel, Hansgeorg, Tenorio, Francisco J., & Martinez, Ana. Reactivity of aluminum cluster anions with ammonia: Selective etching of Al{sub 11}{sup -} and Al{sub 12}{sup -}. United States. doi:10.1063/1.3256236.
Grubisic, Andrej, Li Xiang, Gantefoer, Gerd, Bowen, Kit H., Schnoeckel, Hansgeorg, Tenorio, Francisco J., and Martinez, Ana. Sat . "Reactivity of aluminum cluster anions with ammonia: Selective etching of Al{sub 11}{sup -} and Al{sub 12}{sup -}". United States. doi:10.1063/1.3256236.
@article{osti_21559803,
title = {Reactivity of aluminum cluster anions with ammonia: Selective etching of Al{sub 11}{sup -} and Al{sub 12}{sup -}},
author = {Grubisic, Andrej and Li Xiang and Gantefoer, Gerd and Bowen, Kit H. and Schnoeckel, Hansgeorg and Tenorio, Francisco J. and Martinez, Ana},
abstractNote = {Reactivity of aluminum cluster anions toward ammonia was studied via mass spectrometry. Highly selective etching of Al{sub 11}{sup -} and Al{sub 12}{sup -} was observed at low concentrations of ammonia. However, at sufficiently high concentrations of ammonia, all other sizes of aluminum cluster anions, except for Al{sub 13}{sup -}, were also observed to deplete. The disappearance of Al{sub 11}{sup -} and Al{sub 12}{sup -} was accompanied by concurrent production of Al{sub 11}NH{sub 3}{sup -} and Al{sub 12}NH{sub 3}{sup -} species, respectively. Theoretical simulations of the photoelectron spectrum of Al{sub 11}NH{sub 3}{sup -} showed conclusively that its ammonia moiety is chemisorbed without dissociation, although in the case of Al{sub 12}NH{sub 3}{sup -}, dissociation of the ammonia moiety could not be excluded. Moreover, since differences in calculated Al{sub n}{sup -}+NH{sub 3} (n=9-12) reaction energies were not able to explain the observed selective etching of Al{sub 11}{sup -} and Al{sub 12}{sup -}, we concluded that thermodynamics plays only a minor role in determining the observed reactivity pattern, and that kinetics is the more influential factor. In particular, the conversion from the physisorbed Al{sub n}{sup -}(NH{sub 3}) to chemisorbed Al{sub n}NH{sub 3}{sup -} species is proposed as the likely rate-limiting step.},
doi = {10.1063/1.3256236},
journal = {Journal of Chemical Physics},
number = 18,
volume = 131,
place = {United States},
year = {Sat Nov 14 00:00:00 EST 2009},
month = {Sat Nov 14 00:00:00 EST 2009}
}