Theoretical study of substituent effects on CH stretching frequencies
- 15 September 1984
- journal article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 81 (6) , 2717-2722
- https://doi.org/10.1063/1.447983
Abstract
Substituent effects on CH stretching frequencies are explored by computing isolated CH frequencies of several two- and three-heavy-atom systems containing CH bonds. Effects of polarization functions (6-31G* basis set) and electron correlation (second-order Mo/ller–Plesset perturbation theory MP2) are investigated in all cases. The effects of d functions are mostly small, though significant contributions are seen in some cases. Electron correlation effects are extremely important in describing the CH frequency shifts resulting from substitution of electronegative groups. Frequency shifts calculated at the MP2/6-31G* level are in very good agreement with the corresponding experimental values. Frequency splittings resulting from chemical interaction of equivalent CH bonds and the associated deuterium substitution effects are computed in some cases. Good agreement is obtained in cases where experimental results are available.Keywords
This publication has 23 references indexed in Scilit:
- Analytic energy second derivatives for two-configuration self-consistent-field wave functions. Application to twisted ethylene and to the trimethylene diradicalJournal of the American Chemical Society, 1983
- Second and third derivatives of variational energy expressions: Application to multiconfigurational self-consistent field wave functionsThe Journal of Chemical Physics, 1983
- Analytic force constants for post-Hartree–Fock wave functions: The simplest caseThe Journal of Chemical Physics, 1983
- Unified theoretical treatment of analytic first and second energy derivatives in open-shell Hartree—Fock theoryChemical Physics, 1982
- Effect of electron correlation on theoretical vibrational frequenciesJournal of Computational Chemistry, 1982
- Energy derivatives for configuration interaction wave functionsThe Journal of Chemical Physics, 1981
- Derivative studies in configuration–interaction theoryThe Journal of Chemical Physics, 1980
- Analytic gradients from correlated wave functions via the two-particle density matrix and the unitary group approachThe Journal of Chemical Physics, 1980
- Systematic ab initio gradient calculation of molecular geometries, force constants, and dipole moment derivativesJournal of the American Chemical Society, 1979
- A b i n i t i o computation of force constants. IV. The theoretical anharmonic force fields and vibrational frequencies of methylamine, methanol, and methanethiolThe Journal of Chemical Physics, 1977