High resolution analysis of GeH₄ in the dyad region: Ro-vibration energy structure of ⁷⁰GeH₄ and line strengths of ^MGeH₄ (M = 70, 72, 73, 74, 76)

The infrared spectrum of ^MGeH₄ (M=70,72,73,74,76) was measured at the temperature of (294.5 ± 0.3) K in the 740-960 cm⁻¹ region with a Bruker Fourier transform infrared spectrometer IFS125 and analyzed. The line positions of the ν₂/ν₄ bands and the ro-vibrational energy structure of corresponding upper vibrational states of ⁷⁰GeH₄ were analyzed. The strengths of 1079 experimentally recorded spectral lines (243/270/152/262/152 lines for the isotopologues ⁷⁰GeH₄/⁷²GeH₄/⁷³GeH₄/ ⁷⁴GeH₄/⁷⁶GeH₄) with the value of quantum number J^max = 19 were determined from the fit of their line shapes with a Hartmann–Tran line profile and were used then in the weighted fit for determination of the effective dipole moment parameters of the ν₄ band. The obtained sets of parameters reproduce the initial experimental line intensities with the d_rms=3.46/3.12/3.21/3.38/3.45/% for the ⁷⁰GeH₄/⁷²GeH₄/⁷³GeH₄/ ⁷⁴GeH₄/⁷⁶GeH₄ species, respectively. A list of transitions with their line intensities is generated in the HITRAN format up to the value of quantum number J=40.