INFRARED-EMISSION SPECTRA OF C-3 - THE RENNER EFFECT IN THE A(SIMILAR-TO-3)PI(U) AND B(SIMILAR-TO-3)PI(G) ELECTRONIC STATES

Five new triplet bands of C-12(3), and three corresponding bands of C- 13(3), have been observed in emission between 6000 and 6600 cm(-1) wit h a Fourier transform spectrometer. Rotational analysis shows that the se bands arise from excited bending vibrations of the (b) over tilde(3 ) Pi(g) --> (a) over tilde(3) Pi(u) electronic transition, and that al l components of the (010) vibrational level of the (b) over tilde(3) P i(g) state exhibit unusual perturbations. Renner parameters for both e lectronic states have been extracted from an analysis of the spin-orbi t parameters of the (000) (3) Pi, (010) (3) Delta, (020) (3) Phi, and (030) (3) Gamma levels. The Renner effect is shown to be large in both electronic states (epsilon' = +0.447, epsilon'' = +0.566). Approximat e bending vibrational frequencies are also obtained (omega'(2) similar to 345 cm(-1), omega''2(s)imilar to 505 cm(-1)). (C) 1995 American In stitute of Physics.