Predicted IR spectra of Ti8C12 and

The IR spectra of neutral Ti8C12 metallocarbohedryne (Met-Car) and its cation are predicted based on the complete active space self-consistent field (CASSCF) method. The blue shift predicted for the C–C stretching frequency in Ti 8 C 12 + with respect to neutral Ti8C12 is in agreement with experimental results. The triply degenerate C–C stretching mode splits into doubly and singly degenerate modes as a result of the Ti8C12 Jahn-Teller distortion from Td to D2d symmetry. The splitting is small for the neutral cluster, but it is significant for the cation.