\label{subsec:HBscan} \(\Delta \sigma_{HB}\) and \(\Delta \sigma_{H\alpha B}\) (cf. Eq \ref{eqn:procs}) are parameterized using the model systems shown in Figures \ref{fig:HB} and \ref{fig:HAB}. For \(\Delta \sigma_{HB}\) the scans were done by scanning over the hydrogen bond length \(r_{OH}\), the bond angle \(\theta_{\mathrm{H}}\) defined by H..O=C or H..O-C and the dihedral angle \(\rho_{\mathrm{H}}\) defined by H..O=C-N, H..O=C-C or H..O-C(..)H\(^\text{O}\). The bond length was scanned from 1.5 to 3.0 Å in 0.125 Å steps. \(\theta_{\mathrm{H}}\) was scanned from 180.0 to 90.0\(^\circ\) in 10.0\(^\circ\) steps and \(\rho_{\mathrm{H}}\) was done in the entire range -180\(^\circ\) to 180\(^\circ\). Similarly, for \(\Delta \sigma_{H\alpha B}\) the \(r_{OH\alpha}\) bond length was scanned from 1.8 to 4.0 Å in steps of 0.2 Å. The bond angle \(\theta_{\mathrm{H}\alpha}\) defined by H\(\alpha\)..O=C or H\(\alpha\)..O-C was scanned from 180\(^\circ\) to 90\(^\circ\) with a 10\(^\circ\) step size. The \(\rho_{\mathrm{H}\alpha}\) dihedral H\(\alpha\)..O=C-N, H\(\alpha\)..O=C-C and H\(\alpha\)..O-C(..)H\(^\text{O}\) was scanned in steps of 15\(^\circ\) over the entire range. To get the change in chemical shift caused by the hydrogen bonding the OPBE/6-31G(d,p)//PM6 chemical shielding of systems without hydrogen bonding are subtracted from the scans. The result of the scan is interpolated and saved in another set of .npy files. The monomer geometries are optimized at the PM6 level of theory and kept fixed during the scan.