Germane is a tetrahedral molecule found in trace abundance in giant gas planets like Jupiter and Saturn. We have recently provided a database of calculated lines of the stretching fundamental bands in the 2100 ${\text{cm}}^{-1}$ region that is of high interest for planetology (https://vamdc.icb.cnrs.fr/PHP/GeH4.php). It is now necessary to study many rovibrational levels, including the lowest ones, in order to access the hot bands and thus to improve the model of the spectral region of interest for Jupiter, especially in the framework of the ongoing Juno mission. We present here a complete analysis and modeling of line positions and intensities in the ${\nu }_2/{\nu }_4$ bending dyad region near 900 ${\text{cm}}^{-1}$ for all five germane isotopologues in natural abundance. Thanks to the high symmetry of the molecule, we use the tensorial formalism and group theory methods developed in the Dijon group, that allows us to provide a set of effective Hamiltonian and dipole parameters. The present study also leads to a refined value of the Ge–H equilibrium bond length of 1.51714(25) Å. Finally, new calculated germane lines were derived and injected in the GeCaSDa database.

锗烷是四面体分子，在木星和土星等巨大的气体行星中发现的痕量丰度。我们最近提供了2100年拉伸基带计算线的数据库 ${\text{厘米}}^{-\mathrm{1个}}$ 对行星学非常感兴趣的地区（https://vamdc.icb.cnrs.fr/PHP/GeH4.php）。现在有必要研究许多旋转振动水平，包括最低水平，以便进入热波段，从而改善木星感兴趣的光谱区域的模型，尤其是在正在进行的朱诺飞行任务的框架内。我们在这里介绍了线位置和强度的完整分析和建模。${\nu }_2/{\nu }_4$ 900附近的弯曲二分体区域 ${\text{厘米}}^{-\mathrm{1个}}$ 所有五个自然丰富的德国同位素。由于分子的高度对称性，我们使用了在第戎群中开发的张量形式和群论方法，这使我们能够提供一组有效的哈密顿量和偶极子参数。本研究还得出了Ge-H平衡键长度的精确值1.51714（25）Å。最后，得出新的计算出的锗烷系并将其注入GeCaSDa数据库。