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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. 2009. "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 = 2009,
month =
}
  • The electronic structures and chemical reactivity of the mixed metal sulfide cluster anion (MoWS{sub 4}{sup −}) have been investigated with density functional theory. Our study reveals the presence of two almost isoenergetic structural isomers, both containing two bridging sulfur atoms in a quartet state. However, the arrangement of the terminal sulfur atoms is different in the two isomers. In one isomer, the two metals are in the same oxidation state (each attached to one terminal S). In the second isomer, the two metals are in different oxidation states (with W in the higher oxidation state attached to both terminal S).more » The reactivity of water with the two lowest energy isomers has also been studied, with an emphasis on pathways leading to H{sub 2} release. The reactive behavior of the two isomers is different though the overall barriers in both systems are small. The origin of the differences are analyzed and discussed. The reaction pathways and barriers are compared with the corresponding behavior of monometallic sulfides (Mo{sub 2}S{sub 4}{sup −} and W{sub 2}S{sub 4}{sup −}) as well as mixed metal oxides (MoWO{sub 4}{sup −})« less
  • Photoelectron (PES) spectra from aluminum cluster anions, Al{sub n}{sup {minus}} (12{le}n{le}15), at various temperature regimes, were studied using {ital ab initio} molecular dynamics simulations and experimentally. The calculated PES spectra, obtained via shifting of the simulated electronic densities of states by the self-consistently determined values of the asymptotic exchange-correlation potential, agree well with the measured ones, allowing reliable structural assignments and theoretical estimation of the clusters{close_quote} temperatures. {copyright} {ital 1999} {ital The American Physical Society}
  • Photoelectron spectroscopy is used to investigate aluminum dideuteride cluster anions, Al{sub n}D{sub 2} (n = 3,6-15), produced by laser vaporization of a pure Al target with a D{sub 2}-seeded helium carrier gas. Comparison between the well-resolved photoelectron spectra of Al{sub n}D{sub 2} and Al{sub n} reveals the nature of interactions between D{sub 2} and Al{sub n}. Depending on the size of the Al{sub n} clusters and their electronic structure, three types of Al{sub n}D{sub 2} species are observed, dideuteride (dissociative chemisorption), molecular chemisorption, and physisorption. Striking spectral similarities are observed between photoelectron spectra of Al{sub n}D{sub 2} and Al{sub n}more » for n = 9, 11, 13, and 15, suggesting that D{sub 2} is physisorbed on these closed-shell Al{sub n} clusters. For Al{sub n}D{sub 2} with n = 3, 6, 7, and 10, completely different spectra are observed in comparison with the corresponding Al{sub n} clusters, suggesting that the Al{sub n}D{sub 2} species may be characterized as dideuterides. For Al{sub n}D{sub 2} with n = 8, 12, and 14, in which the Al{sub n} clusters are open shell, the D{sub 2} is characterized as chemisorption on the basis of spectral shifts and similarities relative to those of the corresponding Al{sub n} clusters.« less
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