High resolution study of strongly interacting ν1(A1)/ν3(F2) bands of MGeH4 (M=76, 74)

•High resolution analysis of the ν1/ν3 bands of 74GeH4 and 76GeH4.•Resonance interactions in spherical top molecules.•Determination of spectroscopic parameters.

The infrared spectra of GeH4 were measured in the 1900-2300 cm−1 region with a high resolution of 0.003 cm−1 at different pressures with the Bruker IFS 125HR Fourier transform interferometer (Nizhny Novgorod, Russia) and were analyzed theoretically. 1550 transitions with Jmax.=31 were assigned to the ν3 and ν1 bands of 76GeH4. Rotational, centrifugal distortion, tetrahedral splitting, and resonance interaction parameters for the (0010) and (1000) vibrational states were determined from the fit of experimental line positions. The obtained set of parameters reproduces the initial experimental data with accuracy close to experimental uncertainties. The result of analogous analysis of the 74GeH4 isotopologue (the number of assigned transitions is 750 with Jmax.=27) is presented also.