It would be reasonable to expect the results of the Xe matrix to be similar to those of Ar, since both are atomic matrices. However, the even larger enhancement of cis-CH3ONO when deposited onto a Xe surface alludes to more complicated dynamics at play. In matrix-isolation experiments and molecular dynamics (MD) simulations-specifically those that include guest species with more than one conformer-Xe has consistently been an outlier, and explaining the observations of isolated molecules becomes difficult with the possibility of heavy atom perturbation. While we believe that performing OAD experiments with a Xe matrix would provide more information for understanding the conformer abundance when CH3ONO is isolated in different low-temperature inert matrices, additional angle-dependent experiments in the Xe matrix would not be reasonable to pursue given current Xe availability. We maintain that it is important to show the change between two atomic matrices deposited at the same angle (α = 20°), reinforcing that gas/surface processes are complex even between similar systems. Fig. . Conformer abundance of matrix-isolated CH3ONO in Ar as a function of deposition angle (α) of the cis (blue) and trans (pink) ν3 transition of 500:1 Ar:CH3ONO observed between 1690-1590 cm -1 . The blue and red solid lines represent the gas-phase conformer abundance of 57 ± 2% to 43 ± 2%, where the gas-phase abundance uncertainty is represented in shaded grey. The angle-dependent observations further demonstrate changes in conformer abundances that cannot be explained by a conformational cooling mechanism. In light of the differences observed between different bath gases, we consider differences in the dynamics of matrix deposition between the conformers, including structural and energetic effects. We thus turn to quantum chemistry calculations of 1:1 binding complexes to guide our interpretation.