The First Excited Ca–C–C Bending Vibration Levels in theÃ2Π andX2Σ+States of the CaCCH Radical: The Renner–Teller Effect andK-type Resonance

✍ Scribed by Mingguang Li; John A. Coxon

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 417 KB
• Volume: 180
• Category: Article
• ISSN: 0022-2852
• DOI: 10.1006/jmsp.1996.0251

✦ Synopsis

The 5 1 0 and 5 1 1 bands of the CaCCH A ˜2P-X ˜2S / transition, corresponding to the Ca-C-C bending mode, have been rotationally analyzed through cw dye laser excitation and dispersed fluorescence with a CCD array detector. The upper state is subject to Renner-Teller and spin-orbit couplings, and strong K-type resonance interactions were observed between the nearby 2 D and 2 S vibronic components. A model that invokes a full matrix treatment of these interactions was employed in a least-squares fit of a total of 708 rotational lines of the two bands, recorded with high precision. The fundamental bending frequencies have been determined as n 5 Å 101.394(1) and 102.940(1) cm 01 for the A ˜2P and X ˜2S / electronic states, respectively. The Renner-Teller parameter has been determined as e 5 v 5 Å 3.528( 14) cm 01 . The nonadiabatic parameter for the n 5 mode, g K Å 0.6542(10) cm 01 , is in accord with the observation that the 2 D 5/2 vibronic component lies above the normally highest k 2 S component.