Simplification of the CBS‐QB3 method for predicting gas‐phase deprotonation free energies

International Journal of Quantum Chemistry - Tập 110 Số 2 - Trang 323-330 - 2010
Rodrigo Casasnovas1, Juan Frau1, Joaquín Ortega‐Castro1, Antoni Salvà1, Josefa Donoso1, Francisco Muñoz1
1Institut Universitari d'Investigació en Ciències de la Salut (IUNICS), Departament de Química, Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain

Tóm tắt

AbstractSimplified versions of CBS‐QB3 model chemistry were used to calculate the free energies of 36 deprotonation reactions in the gas phase. The best such version, S9, excluded coupled cluster calculation [CCSD(T)], and empirical (ΔEemp) and spin‐orbit (ΔEint) correction terms. The mean absolute deviation and root mean square thus obtained (viz. 1.24 and 1.56 kcal/mol, respectively) were very‐close to those provided by the original CBS‐QB3 method (1.19 and 1.52 kcal/mol, respectively). The high‐accuracy of the proposed simplification and its computational expeditiousness make it an excellent choice for energy calculations on gas‐phase deprotonation reactions in complex systems. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010

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International Journal of Quantum Chemistry

Tập 110 Số 2

323-330

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