STUDIES ON NUCLEAR MAGNETIC SHIELDING CONSTANTS FOR ISOELECTRONIC SERIES OF THE ATOMS HE, LI, AND BE USING IMPROVED ROOTHAN-HARTREE-FOCK WAVE-FUNCTIONS

Abstract

#A simple theoretical approach is developed to calculate the nuclear magnetic shielding (NMS) constant for atoms He, Li, Be and their isoelectronic series using Roothan-Hartree-Fock (RHF) wave functions which were improved by Koga, et al (1995). The calculations carried out have been extended to the intra- and inter-shells (singlet and triplet states) of atoms and ions to calculate for Κ_α Κ_ρ, K_α L_α, and L _α  L_ρ, to find the contribution from these correlated states to the NMS constant σ. in order to calculate the nuclear magnetic shielding constant, the theoretical relations such as the one particle radial density distribution function Dir) and one particle expectation value (1/r) for all states have been derived analytically and programmed in MATHCAD program The results obtained which are given in tables and in graphical plots are interpreted and discussed in some details. The reliability of the approach is verified by comparing our results with those previously reported