In this section, we compare the intermolecular interactions between CH3ONO and each matrix gas by calculating the binding energies of simple 1:1 complexes (one CH3ONO molecule associated with one bath-gas atom or molecule). We use these 1:1 cluster calculations to identify the range of binding energies for different configurations and conformers. While we recognize the limitations of such models for reproducing binding energies between a complex matrix surface and CH3ONO, calculations of CH3ONO and model matrix surfaces are not performed due to significant computational expense. Furthermore, relevant surface morphologies, which are dynamical quantities, are unknown, increasing the difficulty of developing an appropriate model. With these caveats in mind, we analyze the high-level quantum chemistry calculations of gas:CH3ONO clusters. For reference, the energy difference between cis-CH3ONO and trans-CH3ONO-defined as the energy of the cis conformer minus the energy of the trans conformer in the absence of a bath gas-is -4.39 kJ/mol. We begin our binding energy analysis with the 1:1 complexes formed with N2. From the 22 structures of each conformer evaluated as part of our survey, we identified the lowest energy 1:1 complexes that contain a single N2 molecule and a given conformer of a CH3ONO molecule, shown Fig. , and calculated the binding energies relative to the separated monomers. The binding energy of minimum-energy structure for the cis conformer (1A) is -5.42 kJ/mol, whereas the binding energy of the minimum-energy trans structure (1B) is -4.35 kJ/mol, see Table . The difference in complex binding energies-defined as the 1:1 complex binding energy containing the cis conformer minus the 1:1 complex binding energy containing the trans conformer (ΔEcis -ΔEtrans) for a common bath gas-suggest a difference of -1.08 kJ/mol. The negative energy difference indicates that the N2-van der Waals complex containing the cis conformer is more stable than that containing the trans conformer. For all optimized geometries of N2:CH3ONO, the average binding energy of complexes containing the cis conformer is -3.97 kJ/mol, while all complexes containing the trans conformer have an average binding energy of -3.36 kJ/mol, see Table . Even when considering all possible orientations that result when CH3ONO and N2 form a stabilizing interaction, the difference in average binding energies is -0.61 kJ/mol, where complexes containing cis-CH3ONO demonstrate a slight additional stabilization compared to complexes containing trans-CH3ONO. The preferential binding of N2 to cis-CH3ONO will be discussed in light of the experimentally observed enhancement in Section 4.