Going to ECISD+FDA brings similar improvements of the spectrum as in the symmetric geometry, cutting down the RMSD values of both excitation energies and oscillator strenghts for ≈ 30 -40%. Interestingly, for geometry R 1 , the both RMSD values increase. This observation will be elucidated together with similar examples in the MgG 4 system (Section 5.4.2). Employing ESP embedding systematically improves the performance of both ECIS and ECISD, cutting down the RMSDs of the excitation energies to <0.05 eV and of the oscillator strengths to below 0.1. This provides qualitative agreement with the direct calculations for all geometries, with the exception of states S 6 -S 8 of R 5 . Again, just like on the Frank-Condon geometry of G 4 , when ESP embedding is used, there are only negligible differences between ECIS and ECISD, because the ESP-embedded site states already provide a decent set of excitonic basis functions.