As another approximation, we construct a vibrational exciton model using the anharmonic L-VSCF energy levels for the local-mode vibrations, the harmonic local-mode transition dipole moments and the harmonic coupling constants (L-VSCF exciton model). The corresponding 2D IR spectra are shown in Fig. and, which are almost identical to those from the L-VSCF/L-VCI calculations. This agreement demonstrates that an exciton model with suitable parameters is able to reproduce the results of fully anharmonic L-VSCF/L-VCI calculations, i.e., the approximations that are made in the construction of exciton models 78 are justified here.