Binding Energy of Al(C6H6)+ from Analysis of Radiative Association Kinetics

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• 作者：Robert C. Dunbar ; Stephen J. Klippenstein ; Jan Hru//pubs.acs.org/images/entities/scaron.gif" border="0">á ; k ; Detlef Stö ; ckigt ; and Helmut Schwarz
• 刊名：Journal of the American Chemical Society
• 出版年：1996
• 出版时间：June 5, 1996
• 年：1996
• 卷：118
• 期：22
• 页码：5277 - 5283
• 全文大小：139K
• 年卷期：v.118,no.22(June 5, 1996)
• ISSN：1520-5126

文摘

Analysis of radiative association kinetics is a new andpromising approach to estimating absolute metal-ligand bond energies for gas-phase metal ions. The method isillustrated using previously published data to estimatethe binding energy of aluminum cation to benzene and severaldeuterium-substituted benzenes. A formulation ofradiative association theory is applied which is valid at lowassociation efficiency, and is independent of assumptionsabout the transition state. Photon emission rates from the complexare derived from McMahon-type analysis ofcollisional and radiative association data, and alternatively fromab initio calculations of IR radiativeintensities,with excellent agreement for all four isotopomers. Analysis of theradiative association data gives a binding energyof 1.53 ± 0.10 eV (35.2 ± 2 kcal mol^-1), which isconcordant with, but has a smaller estimated uncertaintythan,an interpolated thermochemical estimate based on data from othermethods. For this system the semiquantitative"standard hydrocarbon" estimate of photon emission rate is a goodapproximation, but it is shown that in order togive valid predictions of the radiative association rate this schemerequires a correction for the fact that one of thereactants is an atomic ion.