Pathways to Detection of Strongly-Bound Inorganic Species: The Vibrational and Rotational Spectral Data of AlH2OH, HMgOH, AlH2NH2, and HMgNH2

Small, inorganic hydrides are likely hiding in plain sight, waiting to be detected toward various astronomical objects. AlH₂OH can form in the gas phase via a downhill pathway, and the present, high-level quantum chemical study shows that this molecule exhibits bright infrared features for anharmonic fundamentals in regions above and below that associated with polycyclic aromatic hydrocarbons. AlH₂OH along with HMgOH, HMgNH₂, and AlH₂NH₂ are also polar with AlH₂OH having a 1.22 D dipole moment. AlH₂OH and likely HMgOH have nearly unhindered motion of the hydroxyl group but are still strongly bonded. This could assist in gas phase synthesis, where aluminum oxide and magnesium oxide minerals likely begin their formation stages with AlH₂OH and HMgOH. This work provides the spectral data necessary to classify these molecules such that observations as to the buildup of nanoclusters from small molecules can possibly be confirmed.