Nuclear magnetic resonance J coupling constant polarizabilities of hydrogen peroxide: a basis set and correlation study.
ABSTRACT In this article, we present the so far most extended investigation of the calculation of the coupling constant polarizability of a molecule. The components of the coupling constant polarizability are derivatives of the nuclear magnetic resonance (NMR) indirect nuclear spin-spin coupling constant with respect to an external electric field and play an important role for both chiral discrimination and solvation effects on NMR coupling constants. In this study, we illustrate the effects of one-electron basis sets and electron correlation both at the level of density functional theory as well as second-order polarization propagator approximation for the small molecule hydrogen peroxide, which allowed us to perform calculations with the largest available basis sets optimized for the calculation of NMR coupling constants. We find a systematic but rather slow convergence with the one-electron basis set and that augmentation functions are required. We observe also large and nonsystematic correlation effects with significant differences between the density functional and wave function theory methods.
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ABSTRACT: A correlation-energy formula due to Colle and Salvetti [Theor. Chim. Acta 37, 329 (1975)], in which the correlation energy density is expressed in terms of the electron density and a Laplacian of the second-order Hartree-Fock density matrix, is restated as a formula involving the density and local kinetic-energy density. On insertion of gradient expansions for the local kinetic-energy density, density-functional formulas for the correlation energy and correlation potential are then obtained. Through numerical calculations on a number of atoms, positive ions, and molecules, of both open- and closed-shell type, it is demonstrated that these formulas, like the original Colle-Salvetti formulas, give correlation energies within a few percent.Physical review. B, Condensed matter 02/1988; 37(2):785-789.
- ChemPhysChem 05/2003; 4(4):395-9. · 3.35 Impact Factor
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ABSTRACT: Three medium-size optically active molecules have been studied to make a guess at candidates suitable for chiral discrimination in an isotropic medium via nuclear magnetic resonance spectroscopy. The criterion for experimental detection is given by the magnitude of the isotropic part of nuclear magnetic shielding polarisability tensors, related to a pseudoscalar of opposite sign for the two enantiomers. The pseudoscalar shielding polarisability at the (17)O nucleus in N-methyloxaziridine, calculated at the Hartree-Fock level, is approximately 7.8 x10(-)(17) mV(-)(1). To obtain an experimentally observable magnetic field induced at the (17)O nucleus in N-methyloxaziridine, electric fields as large as approximately 10(7) - 10(8) Vm(-)(1) should be applied to the probe. The molecular electric dipole moment induced by precession of the magnetic dipole of the (17)O nucleus in a magnetic field of 10 T is, in absolute value, approximately 8.8 x 10(-)(42) Cm. The estimated rf-voltage at a resonance circuit is approximately 10 nV. Smaller values have been estimated for N, C, and H nuclei in 1,3-dimethylallene and 2-methyloxirane.Journal of Computational Chemistry 11/2007; 28(13):2159-63. · 3.84 Impact Factor