Louis Caralp

Extended London theory of diamagnetism. I. General theory and saturated hydrocarbons

In this paper a method is proposed to calculate diamagnetic susceptibilities of organic compounds. This method uses the extended Huckel formalism generalized to include the perturbation due to a magnetic field H. Parameters are varied to obtain agreement with experimental results. The diamagnetic properties of the alkanes are examined and all the terms contributing to the susceptibility are analyzed. The importance of a coupling term between matrix elements of first order in H and London terms is shown. Some results are discussed, particular to methane and the cycloalkanes.

Extended London theory of diamagnetism Unsaturated hydrocarbons

The extended London theory of diamagnetism is applied to the calculation of the susceptibilities and the anisotropies of unsaturated hydrocarbons. The agreement with experimental results is good.

Méthode cndo et détermination des constantes de force

Abstract Binding force constants calculated by the CNDO II method are very sensitive to the second order derivative of H μ,ν integrals between orbitals of bonded atoms. This sensitivity is used to obtain a parametric form of these integrals, from which satisfactory force constants for carbon—carbon and carbon—hydrogen bonds are derived. All other characteristics of the method are preserved. The reasons for the observed correlation between bond indices and force-constants are analyzed.

Determination des geometries d'equilibre et des constantes de forces par une methode de type CNDO

Abstract A CNDO/2 parametric adaptation including Fischer-Kollmar and Sadlej modifications is made. This method leads to much better agreement between theory and experiment for bonding force constants of diatomic molecules and ethylenic and saturated hydrocarbons. However, these force constants are very sensitive to first and second derivatives of molecular integrals, so it is not possible to obtain a unique parametric formulation for various types of bond.