The Theory of Chemical Shifts in the Hartree-Fock Approach.
DUKE UNIV DURHAM N C DEPT OF CHEMISTRY
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The general theory of chemical shifts has been well known since the paper of Ramsey in 1950. With the development of improved methods for obtaining new Hartree-Fock wave functions interest has again been rekindled to theoretically determine the chemical shift tensor in this approximation. The purpose of this report is to present what is believed to be a thorough and, hopefully, clear derivation of the theoretical expressions in what appears to be the most transparent approach. Following a brief review of the pertinent Hamiltonian, the Hellmann-Feynmann theorem is used to establish the general shift expression. This is followed by a discussion of Londons approach to the origin-gauge problem and perturbed Hartree-Fock theory in a variable basis set. Finally, the chemical shift equations are derived by employing Londons approach. Author
- Quantum Theory and Relativity