PREDICTION OF B-11 QUADRUPOLE COUPLING-CONSTANTS IN MOLECULES

The B3LYP/6-31G(df, p) model is shown to be a viable alternative to th e computationally demanding MP2/6-311G(3df, 3pd) model for the predict ion of B-11 nuclear quadrupole coupling constants in molecules. Using eQ/h as a best fit parameter, coupling constants calculated with the B 3LYP model show a root mean square (rms) deviation of 0.059 MHz from t he experimental values for 11 molecules; those calculated with the MP2 model, 0.049 MHz. Comparison of coupling constants predicted by the t wo models for a sample size increased to 25 molecules yields a rms dif ference between models of 0.036 MHz. (C) 1997 Academic Press.