Abstract
Ab initio nuclear magnetic shielding surfaces were obtained for all nuclei for CH3F, CH3Cl and CH3Br in terms of curvilinear coordinates using an SCF-CHF/LORG procedure and moderately large basis sets to overcome the gauge dependence problem. The shielding surfaces for C, F, Cl and Br are complete up to second order and can be employed to calculate isotope and temperature effects in CH3X molecules, X = F, Cl, Br.