The vibronic structure superimposed on the benzene Rydberg transition corresponding to 3e1u(r) → 3s(a1g) excitation at 11 eV has been studied spectroscopically. The revealed structure is interpreted in terms of two Rydberg systems deriving from 3e2g(σ) → 6p(e1u) and 3e2g(σ) → 6f(b1u, b2u, e1u, e2u) which fit respectively the δ = 0.47 and δ = 0.3 Rydberg series converging to the second ionization limit. In n = 6; δ = 0.3 the pure electronic band as well as the 0-1 band corresponding to ν2(a1g) split upon reducing the vibrational symmetry to D2h by suitable deuterations whereas no such splitting was detected on the 0-1 band corresponding to the Jahn-Teller active mode ν18(e2g). The same pattern is revealed in n = 4 of the same Rydberg series. This pattern is accounted for theoretically.
ASJC Scopus subject areas
- Physics and Astronomy (all)
- Physical and Theoretical Chemistry