“…The molecular eigenstate spectra of pyrazine belonging to the 0−0 band of the S 0 → S 1 transition have been precisely examined first by van der Meer et al with an ultrahigh-resolution of ∼10 MHz, and the energies and intensities of the spectra belonging to the P(1) transition are given for the 12 strongest states. The same group showed that it is possible to relate the spectra observed for the P(1) transition to the S−T mixed states composed of a zero-order singlet state with J’ = 0 and 11 zero-order triplet states by a trial-and-error method, which are denoted by |S〉 and {|T j 〉} in eq 3 . Lawrance and Knight reanalyzed the data by using a more elegant deconvolution procedure, and {|T j 〉} located at −2821.5, −2495.4, −1380.5, −518.7, −340.9, −304.1, −90.7, −8.8, 436.7, 619.7, and 816.3 MHz were shown to interact with the S 1 origin with J’ = 0 with the coupling strengths of 289.3, 228.4, 287.0, 84.0, 53.8, 75.9, 129.5, 127.5, 422.7, 79.0, and 56.0 MHz, respectively.…”