Nuclear magnetic resonance shielding constants in XH4 group XIV hydrides

Self-consistent field and multiconfigurational self-consistent field wave functions are used to analyse NMR shielding constants in the XH4 hydrides, X C, Si, Ge, Sn and Pb. All relativistic corrections to order alpha 4, where alpha is the fine structure constant, are included in the evaluation of the perturbation corrections to the non-relativistic shielding constants. Each of the relativistic corrections is compared to the results obtained for group XVI and XVII hydrides and noble-gas atoms. For the heavy nuclei, the computed relativistic corrections can be used to improve the absolute shielding scale.