Anomalous Raman shift in the ternary fullerides with t(1g) states

Raman spectra have been studied on two kinds of highly doped fullerides of A(x)Ba(3)C(60) (x = 0,3; A = K, Rb) and KxSm2.75C60 (x = 0,3.25). It was fo und that the Raman spectra are essentially identical to each other for all ternary fullerides. The results show a crossover point at the boundary of t (1u) and t(1g) bands for the charge-transfer dependence of Raman shift. Par ticularly, the totally symmetric A(g)(2) mode in t(1g) fullerides cannot be understood by a simple extrapolation from the low-doped t(1u) fullerides, where the A(g)(2) mode follows a characteristic shift of similar to 6.3 cm( -1) per elementary charge. The present result shows that the Raman spectra of t(1g) states cannot be explained only by charge transfer. [S0163-1829(99 )01737-3].