High resolution spectra of GeH4 <i>v</i>=6 and 7 stretch overtones. The perturbed local mode vibrational states

Abstract

Here we report the preliminary analysis of the high resolution spectra of 70GeH4 (6000) and (7000) stretch overtone bands obtained by intracavity laser absorption spectroscopy (ICLAS). The observed P(J+1), Q(J), and R(J−1) transitions agree well with the combination difference relations, indicating that the Coriolis coupling in the degenerate states is negligible. This is an important feature for a spherical top molecule near the local mode limit. The vibration–rotational energy levels of upper states as well as those of some perturber states are obtained. The improved local mode parameters of GeH4 are also derived.