Pseudo-Jahn-Teller effect as the origin of the exalted frequency of the b2u Kekulé mode in the 1(1)B2u excited state of benzene.
In this paper we show that a pseudo-Jahn-Teller (PJT) coupling between the (1)A1g ground state and the (1)B2u excited states along the Kekulé mode of b2u symmetry is responsible for the surprisingly low frequency of this mode in the ground state and its remarkable upward shift of 261 cm(-1) upon excitation to the first (1)B2u excited state.
Blancafort
Lluís
L
Solà
Miquel
M