EXACT ZERO-POINT ENERGY SHIFT IN THE E-CIRCLE-TIMES(NE), T-CIRCLE-TIMES(NH) MANY-MODES DYNAMIC JAHN-TELLER SYSTEMS AT STRONG-COUPLING

We find the exact semiclassical (strong coupling) zero-point energy sh ifts applicable to the e x (nE) and t x (nH) dynamic Jahn-Teller probl ems, for an arbitrary number n of discrete vibrational modes simultane ously coupled to one single electronic level. We also obtain an analyt ical formula for the frequency of the resulting normal modes, which ha s an attractive and apparently general Slater-Koster form. The Limits of validity of this approach are assessed by comparison with O'Brien's previous effective-mode approach, and with accurate numerical diagona lizations. Numerical values obtained for t x (nH) with n = 8 and coupl ing constants appropriate to C-60(-) are used for this purpose, and ar e discussed in the context of fullerene. [S0163-1829(98)05526-X].