Document Detail

Formation and ionization energies of small chlorine-doped lithium clusters by thermal ionization mass spectrometry.
MedLine Citation:
PMID:  22279020     Owner:  NLM     Status:  In-Data-Review    
RATIONALE: Theoretical calculations have shown that the first ionization energy of clusters of the type Li(n) Cl (n ≥2), with more than eight valent electrons, is lower than that of alkali metal atoms; hence they are named superalkali. Superalkali clusters can mimic the chemical behavior of alkali metals and may be used as building blocks of new cluster-assembled materials. There is currently no reliable experimental proof of this kind of clusters and such proof is required.
METHODS: The Li(n) Cl (n = 2-6) clusters were produced by a thermal ionization source of modified design, and mass selected by a magnetic-sector mass spectrometer. The modification pertains to the replacement of the side filaments by a cylinder in the triple-filament thermal ionization source. The sample, which is LiCl salt, was pressed into a ring and placed on the inner wall of the cylinder.
RESULTS: It was observed that the ions of clusters with an even number of lithium atoms (Li(2) Cl(+) , Li(4) Cl(+) , Li(6) Cl(+) ) are more stable than the odd-numbered ones (Li(5) Cl(+) , Li(3) Cl(+) ). The ionization energies were determined to be 3.98 ± 0.25 eV for Li(2) Cl, 4.10 ± 0.25 eV for Li(3) Cl, 3.90 ± 0.25 eV for Li(4) Cl, 4.01 ± 0.25 eV for Li(5) Cl, and 4.09 ± 0.25 eV for Li(6) Cl. The presence of a halogen atom reduces the ionization energy of the metal clusters.
CONCLUSIONS: The thermal ionization source of modified design presents a suitable simple way to obtaining and measuring the ionization energies of very small lithium monochloride clusters. Clusters Li(n) Cl, n = 4 to 6, were detected for the first time. Copyright © 2012 John Wiley & Sons, Ltd.
S R Veličković; J B Djustebek; F M Veljković; B B Radak; M V Veljković
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Rapid communications in mass spectrometry : RCM     Volume:  26     ISSN:  1097-0231     ISO Abbreviation:  Rapid Commun. Mass Spectrom.     Publication Date:  2012 Feb 
Date Detail:
Created Date:  2012-01-26     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8802365     Medline TA:  Rapid Commun Mass Spectrom     Country:  England    
Other Details:
Languages:  eng     Pagination:  443-8     Citation Subset:  IM    
Copyright Information:
Copyright © 2012 John Wiley & Sons, Ltd.
VINČA Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001, Belgrade, Serbia.
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