A 1ST-PRINCIPLES STUDY OF THE INFLUENCE OF FLUORINE FLUORINE INTERACTIONS ON THE NUCLEAR-QUADRUPOLE PARAMETERS IN FLUOROBENZENES

The nuclear quadrupole interaction parameters e2qQ and eta are calcula ted for fluorine nuclei in fluorobenzenes from wave functions obtained using a first-principles Hartree-Fock procedure utilizing linear comb inations of atomic orbitals. Weighted averages of these individual par ameters are used in an attempt to explain results obtained from time-d ependent perturbed angular distribution measurements made earlier on v arious fluorobenzene samples implanted with F-19. Six different basis sets were used. Agreement between the calculated and experimental res ults for e2qQ was within 16% in all cases and within 3% for two of the basis sets used, and the trend in e2qQ with increasing fluorine subst itution was successfully predicted. The asymmetry parameter calculatio ns yielded results in good overall agreement with experiment.