摘要: Two photon photoacoustically detected spectra are reported for the first excited singlet state 1E' of sym-triazine in the gas phase. The origin has been positively identified as of E' symmetry through contour calculations and hot ... 展开 Two photon photoacoustically detected spectra are reported for the first excited singlet state 1E' of sym-triazine in the gas phase. The origin has been positively identified as of E' symmetry through contour calculations and hot band observations. The excited state absorption is dominated by a highly irregular progression. Observations are strongly supported by a Jahn Teller calculation which predicts: little coupling between A'2 and E' electronic manifolds; a large quadratic coupling and a small linear coupling in the E' manifold; and a quenched angular momentum in this state. Good agreement is shown to exist between one photon and two photon spectroscopic observations and the calculations. 收起