VARIATIONAL CALCULATION FOR LARGE BIPOLARONS IN ARBITRARY DIMENSIONS

The calculation model of the large bipolaron binding energy proposed b y Verbist et al. is extended to arbitrary dimensions including fractal dimensions. It is found that the fractal dimension D = 1.25 correspon ds to the lowest critical coupling constant alpha(c) = 1.9, D = 1.73 c orresponds to the highest critical ratio of dielectric constants eta(c ) = 0.163, and when D less-than-or-equal-to 1.145 bipolarons can not e xist fox any coupling constants and ratios of dielectzic constants.