Low-lying bending vibronic bands of the MgNC A 2Pi-X 2Sigma+ transition.
We have generated MgNC in supersonic free jet expansions and measured the laser induced fluorescence excitation spectra of the Mg-N-C bending vibronic bands of the A 2Pi-X 2Sigma+ transition. In addition to the two vibronic bands, 2(0) (1), kappa 2Sigma(+)- and 2(0) (2), kappa 2Pi-2Sigma+, reported previously, the 2(0) (2), mu 2Pi1/2-(2)Sigma+ vibronic subband was found just above the 2(0) (1) band. The most remarkable feature of this subband is unexpected rotational structure of the A (020) mu 2Pi1/2 level, showing the splitting of the e and f sublevels. On the basis of the fact that the A (020) mu 2Pi1/2 level lies very close to the A (010) kappa2Sigma+ level, the ef splitting is ascribed to P-type doubling which is induced by Coriolis interaction between these two bending vibronic levels. Introducing the Coriolis coupling terms arising from the G-uncoupling operator, -J+/-G22-/+, and the spin-Coriolis interaction, S+/-G22-/+, into the rotational Hamiltonian, this unexpected rotational structure has been analyzed. This P-type doubling would be one of the rare examples exhibiting the Coriolis interaction between two bending vibronic levels with Deltav2=+/-1 and Deltal=-/+1. Through the molecular constants of the A (010) kappa 2Sigma+, (020) kappa 2Pi, and mu 2Pi1/2 levels, the Renner-Teller vibronic structure of the nu2 bending mode in the A 2Pi state has been characterized. The observed vibronic bands analyzed in this study show some anomalies in the band intensities. Based on the information of the nu2 bending vibronic structure derived from the present analyses, we discuss the intensity anomalies.
Faculty of Information Sciences, Hiroshima City University, Hiroshima 731-3194, Japan. fukushim@im.hiroshima-cu.ac.jp
Masaru
M
Fukushima
Takashi
T
Ishiwata