The out-of-plane vibrational modes of chlorobenzene in its ground and first singlet excited states

The study of 2699 Å electronic band system of chlorobenzene has been extended to extract out all the six b₁ and three a₂ modes in both the ground state (^eA₁) and the electronically excited first singlet state (^eB₂). The procedure of the extraction of these modes on the basis of observed sequences, cross-sequences, and overtones has especially been elaborated. Strong Fermi interaction has been observed between the vibrational level ν′_6b and combination level ν′_16a + ν′_16b in ^eB₂ state. The uniqueness of the assignments of the modes has been critically discussed.