Comparing our calculated 2D IR spectra to the experimental spectra recorded in solution and in the gas-phase shows an overall good agreement (see also Table ). Note that in experiment the peaks are broadened because of additional dynamical effects that are not included in our static calculations. As for DAR, the positions of the fundamentals are shifted, but the splitting between the two vibrational modes are reproduced quite well (28 cm -1 vs. 21 cm -1 in the experimental spectrum). The splitting of the anhamonically shifted peaks in not resolved in experiment, but the anharmonic shifts are in very good agreement. Table V: Local-mode frequencies and coupling constants used in the vibrational exciton models for DKP and NAGMA. Values obtained within the harmonic approximation are given for comparison. For the L-VSCF exciton models, the local-mode frequencies are extracted from the anharmonic L-VSCF calculations. For the ∆-exciton models, an anharmonic shift of ∆ = 4 cm -1 and of ∆ = 7 cm -1 is applied for DKP and NAGMA, respectively. All values are given in cm -1 . The 2D IR spectra of DKP and NAGMA calculated with L-VSCF/L-VCISD with anharmonic one-mode and harmonic two-mode potentials are shown in Fig. , b and in Fig. , respectively. The parameters of the vibrational exciton models based on our harmonic and L-VSCF calculations are listed in Table . The 2D IR spectra calculated using L-VSCF/L-VCISD with full anharmonic two-mode potentials as well as those based on the L-VSCF and ∆-exciton models are given in Figs. S1 and S2 in the Supporting Information. As for the previous test cases, the 2D IR spectra calculated with all four approaches are almost indistinguishable. Table in the Supporting Information further lists the fundamental transition frequencies as well as anharmonic shifts extracted from our calculations.