Gas-phase measurements of hydrated clusters are extremely difficult to carry out. One promising technique to identify weakly bound clusters is to probe the H-shift of the O-H stretch upon cluster formation. This methodology has been applied to detect clusters such as the gas-phase PA monomer, 63 the gas-phase dimethylamine monomer, 110 and the gasphase methanol-dimethylamine dimer 111 where the N-H stretch is contributing to cluster formation. However, to the best of our knowledge, there are no previous studies on the IR absorptions of hydrated PA clusters in the gas-phase. Here we provide such analysis to potentially guide future experiments. The IR spectra presented in this section were obtained at ωB97X-D/6-31++G(d,p) level of theory. We stress that the choice of method is qualitatively sufficient for the following analysis. I.e. the peaks in the IR spectra are likely shifted compared experimental values, but the overall relative peak positions should accurate. As the PA monomer is found not to be hydrated in the gas-phase a strong red-shift from 3725 cm -1 in an experiment could indicate that the PA monomer is interacting with one or more water molecules. This streching frequency mode for the gas-phase PA monomer is also in fairly good agreement with previously reported experimental work. compared to the PA monomer. In addition, we observe the O-H frequencies to increase with increasing water content while the intensities decrease. This is in contrast to the hydrated PA clusters with no ions present.