INTRACAVITY LASER-ABSORPTION SPECTROSCOPY OF CHD3 FROM 10800 TO 18000 CM(-1)

High resolution absorption spectroscopy of the CHD3 molecule has been completed by a systematic study between 10800 and 18000 cm-1. Due to the very low intensity of the overtone bands in this energy range, the spectrum was recorded using the intracavity laser absorption spectroscopy (ICLAS) technique. A new ICLAS spectrometer using a Ti:sapphire crystal as amplification medium has been developed to record the near infrared spectrum. Seven new bands have been rotationally resolved and are reported for the first time. The vibrational analysis of the complete set of data available up to now (36 bands) can be performed using a Dunham expansion or by taking into account explicitly the strong Fermi resonance between the nu1(A1) CH stretching and the nu5(E) bending mode. The CH stretching motion is also coupled with the CD stretching and the corresponding bands are well accounted by the standard local mode model. Two other unexpected bands observed at 12235 and 14753 cm-1 have been assigned to combination bands involving the nu3(A1) mode.