All quantum chemical computations were performed with Q-Chem 5.4. Minimum energy structures of both cis and trans conformers of CH3ONO bound to a single matrix-gas component, X:CH3ONO (X = N2, Ar, or Xe), are calculated. Twenty-two initial configurations of each 1:1 complex were generated, with the bath gas placed around either the cis-CH3ONO or trans-CH3ONO molecule. Geometry optimizations were performed using the B3LYP density functional with Grimme's D3(BJ) dispersion correction and cc-pVDZ basis set. For Xe, the cc-pVDZ-PP basis set and corresponding ECP were used. Zero-point energy corrections were computed via harmonic frequency analysis at the same level of theory. Relative energies of the clusters are refined via single-point energy calculations with coupled cluster theory, employing single, double and perturbative triple excitations, CCSD(T) , and an aug-cc-pVDZ basis set for all atoms except Xe, for which the aug-cc-pVDZ-PP basis and corresponding ECP were used. Binding energies of the X:CH3ONO complex were computed as differences in the zero-point energy corrected CCSD(T) single-point energies between the X:CH3ONO complex and infinitely separated X compound and CH3ONO molecule.