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Two molecular properties, the nuclear electromagnetic hypershielding (ψ γ,αΒ ′) and the gradient of the electric dipole-magnetic dipole polarizability (∇ γ G ′), have been calculated using the time-dependent Hartree-Fock method. Provided the Hellmann-Feynman theorem is satisfied, these quantities are equivalent and are related through the ∇Iγ G αΒ ′ =e ZI ψ γ,αΒ ′I relation, where ZI is the atomic number of atom I and e the magnitude of the electron charge. In such a case, the determination of the nuclear electromagnetic hypershielding presents the computational advantage over the evaluation of the gradient of G αΒ ′ of requiring only the knowledge of nine mixed second-order derivatives of the density matrix with respect to both electric and magnetic fields (Dα,Β (-ω,ω)) instead of the 3N (N is the number of atoms) derivatives of the density matrix with respect to the Cartesian coordinates (D ). It is shown here for the H O molecule that very large basis sets such as the aug-cc-pVQZ or the R12 basis are required to satisfy the Hellmann-Feynman theorem. These basis set requirements have been substantiated by considering the corresponding rototranslational sum rules. The origin dependence of the rototranslational sum rules for the gradient of G αΒ ′ has then been theoretically described and verified for the H O molecule.
Elaboration of quantum chemistry methods for predicting and interpreting vibrational Raman optical activity: applications to helical structuresAuthor: Liégeois, V., 19 juin 2008
Thèse de l'étudiant: Doc types › Docteur en Sciences