ANHARMONIC CONSTANTS FOR BENZENE

The anharmonic constants x(pq), g(pq) are recomputed for C6H6, using a previously obtained self consistent field quartic forcefield. Particu lar care has been taken to obtain correct values for the anharmonic co nstants when p and q refer to degenerate modes t and t', by treating t he molecule as an asymmetric top. The Pliva formulae have been verifie d for x(tt), g(tt), x(tt') and g(tt'). Values for the vibrational l-ty pe doubling constants r(tt'), s(tt') have also been determined. The im portance of Fermi-I and Fermi-II resonances has also been examined. (C ) 1997 Elsevier Science B.V.