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1.
Phys Rev Lett ; 107(17): 173401, 2011 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-22107515

RESUMO

The geometry of cationic silicon clusters doped with vanadium, Si(n)V(+) (n=12-16), is investigated by using infrared multiple photon dissociation of the corresponding rare gas complexes in combination with ab initio calculations. It is shown that the clusters are endohedral cages, and evidence is provided that Si(16)V(+) is a fluxional system with a symmetric Frank-Kasper geometry.

2.
J Chem Phys ; 133(21): 214304, 2010 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-21142301

RESUMO

The geometric structures of small cationic rhodium clusters Rh(n)(+) (n = 6-12) are investigated by comparison of experimental far-infrared multiple photon dissociation spectra with spectra calculated using density functional theory. The clusters are found to favor structures based on octahedral and tetrahedral motifs for most of the sizes considered, in contrast to previous theoretical predictions that rhodium clusters should favor cubic motifs. Our findings highlight the need for further development of theoretical and computational methods to treat these high-spin transition metal clusters.

3.
J Chem Phys ; 132(1): 011101, 2010 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-20078142

RESUMO

The geometric structure of the Rh(8) (+) cation is investigated using a combination of far-infrared multiple photon dissociation spectroscopy and density functional theory (DFT) calculations. The energetic ordering of the different structural motifs is found to depend sensitively on the choice of pure or hybrid exchange functionals. Comparison of experimental and calculated spectra suggests the cluster to have a close-packed, bicapped octahedral structure, in contrast to recent predictions of a cubic structure for the neutral cluster. Our findings demonstrate the importance of including some exact exchange contributions in the DFT calculations, via hybrid functionals, when applied to rhodium clusters, and cast doubt on the application of pure functionals for late transition metal clusters in general.

4.
J Chem Phys ; 129(12): 124304, 2008 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-19045020

RESUMO

Density functional theory is used to investigate the structures of cationic rhodium cluster oxides, Rh(6)O(m) (+) (m=1,4). On the monoxide and dioxide, the oxygen atoms occupy bridge sites, while on trioxide and tetroxide clusters, high-coordination sites are favored. A range of spin multiplicities are investigated for each cluster, with high spin multiplicities found to be less favored for the oxides compared with the naked metal clusters. The dissociation of nitric oxide on low-energy isomers of Rh(6)O(4) (+) is investigated and found to be unfavorable compared to molecular adsorption due to a combination of thermodynamic and kinetic factors. These calculations are consistent with, and help to account for, the experimentally observed reactivity of rhodium and rhodium oxide clusters with nitric oxide [M. S. Ford et al., Phys. Chem. Chem. Phys. 7, 975 (2005)].

5.
Am J Hosp Palliat Care ; 8(4): 20-2, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1931327

RESUMO

This paper reviews the history of St. Anthony's Hospice and Life Enrichment Program. St. Anthony's provides bereavement counseling and death education to the community using a networking approach involving the educational, religious, social, and mental health organizations in the area. At present, this model features a church satellite program, grief recovery and anticipatory grief seminars, on-going bereavement support and social support groups, volunteer speakers' bureau, a volunteer staffed bereavement team, and training of psychology, nursing, and medical students.


Assuntos
Luto , Relações Comunidade-Instituição , Hospitais para Doentes Terminais/organização & administração , Apoio Social , Pesar , Hospitais para Doentes Terminais/métodos , Humanos , Psicoterapia de Grupo , Texas , Voluntários
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