Z. LIU, W. Y. FAN AND P. B. DAVIES, Department of Chemistry, Uiversity of Cambridge, Cambridge CB2 1EW, UK.
The pure rotational quasibound spectra of HeH+ and HeD+ have been observed in the mid infrared region using diode laser velocity modulation absorption spectroscopy. Four quasibound to quasibound(Q-Q) and three bound to quasibound(B-Q) transitions of HeH+ and one bound to quasibound transition of HeD+ have been detected in a low pressure ac glow discharge. The highest quasibound level involved in the spectra (HeH+, v=0, J=26) is 2000 cm-1 above the dissociation limit. The measured transition frequencies are in very good agreement with ab intio calculations. Two of the Q-Q transitions have wider linewidths due to lifetime broadening.