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Performance of PNOF5 Natural Orbital Functional for Radical Formation Reactions: Hydrogen Atom Abstraction and C–C and O–O Homolytic Bond Cleavage in Selected Molecule

Radical formation through hydrogen abstraction and C-C and O-O homolytic bond cleavage from selected molecules is investigated by use of natural orbital functional theory in its PNOF5 natural orbital functional implementation, and the results are compared to high-level ab initio complete active space self-consistent field (CASSCF) and complete active space with second-order perturbation theory (CASPT2) methods and experimental data. It is observed that PNOF5 is able to treat the strong electron correlation effects along the homolysis of X-H (X = C, N, O) and X-X (X = C, O) bonds, leading, in general, to the correct trends in the corresponding bond strengths and a good description of the resultant electronic structure for these radicals. In general, PNOF5 bond energies are lower than the experimental ones, because of partial lack of dynamical electron correlation. However, the part of dynamical electron correlation recovered by PNOF5 allows it to give more accurate results than CASSCF methods with a minimum window required to treat near-degeneracy effects. In addition, inspection of the natural orbital occupancies with respect to the CASSCF ones shows an outstanding performance of PNOF5 in treating degenerate and quasidegenerate states, giving a correct description of diradicals and diradicaloids formed upon C-C cleavage in cyclopropane and derivatives

© Journal of Chemical Theory and Computation, 2012, vol. 8, núm. 8, p. 2646-2652

American Chemical Society

Autor: Lopez, Xabier
Ruipérez, Fernando
Piris, Mario
Matxain, Jon M.
Matito i Gras, Eduard
Ugalde, Jesus M.
Data: 2012
Resum: Radical formation through hydrogen abstraction and C-C and O-O homolytic bond cleavage from selected molecules is investigated by use of natural orbital functional theory in its PNOF5 natural orbital functional implementation, and the results are compared to high-level ab initio complete active space self-consistent field (CASSCF) and complete active space with second-order perturbation theory (CASPT2) methods and experimental data. It is observed that PNOF5 is able to treat the strong electron correlation effects along the homolysis of X-H (X = C, N, O) and X-X (X = C, O) bonds, leading, in general, to the correct trends in the corresponding bond strengths and a good description of the resultant electronic structure for these radicals. In general, PNOF5 bond energies are lower than the experimental ones, because of partial lack of dynamical electron correlation. However, the part of dynamical electron correlation recovered by PNOF5 allows it to give more accurate results than CASSCF methods with a minimum window required to treat near-degeneracy effects. In addition, inspection of the natural orbital occupancies with respect to the CASSCF ones shows an outstanding performance of PNOF5 in treating degenerate and quasidegenerate states, giving a correct description of diradicals and diradicaloids formed upon C-C cleavage in cyclopropane and derivatives
Format: application/pdf
ISSN: 1549-9618
Accés al document: http://hdl.handle.net/10256/7291
Llenguatge: eng
Editor: American Chemical Society
Col·lecció: Reproducció digital del document publicat a: http://dx.doi.org/10.1021/ct300414t
Articles publicats (D-Q)
info:eu-repo/grantAgreement/EC/FP7/294240
És part de: © Journal of Chemical Theory and Computation, 2012, vol. 8, núm. 8, p. 2646-2652
Drets: Tots els drets reservats
Matèria: Dinàmica molecular
Molecular dynamics
Fisicoquímica
Chemistry, Physical and theorical
Dissociació (Química)
Química quàntica
Quantum chemistry
Títol: Performance of PNOF5 Natural Orbital Functional for Radical Formation Reactions: Hydrogen Atom Abstraction and C–C and O–O Homolytic Bond Cleavage in Selected Molecule
Tipus: info:eu-repo/semantics/article
Repositori: DUGiDocs

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