FARADAY LASER MAGNETIC-RESONANCE SPECTROSCOPY OF VIBRATIONALLY EXCITED C2D

We studied the gas phase spectrum of the deuterated ethynyl radical C2 D in the region between 3196 and 3243 cm(-1) using a Faraday LMR spect rometer in combination with a CO overtone laser. The C2D radicals were generated in a dc glow discharge containing helium, deuterium, and ac etylene. We observed a hot band between two vibronic in states with an origin at 3225 cm(-1).The lower level is assigned to the first excite d bending level of the electronic X ground stale. The upper level corr esponds to the first excited electronic slate A at 3513 cm(-1), which was observed previously [J. Mel. Struct. 190, 41-60 (1988)]. This regi on is subject to strong vibronic interaction, caused by mixing of the electronic X ground state with the A state at 3513 cm(-1). From the an alysis of the spectra we could determine the orbital g factor of the u pper level, which gave important information about the mixing ratios. In addition we were able to derive a precise term value for the first excited bending level of the electronic X ground state. The experiment ally derived molecular parameters are compared with theoretically calc ulated values, obtained by ab initio calculations. (C) 1998 Academic P ress.