The circular dichroism (CD) studies of bis-1,8-naphthalimide. The theoretical analysis in terms of density functional and vibronic dimer theories

The vibronic coupling theory is applied to study the absorption and circular dichroism (CD) spectra of bis-1,8-naphthalimide molecule considered as a dimer with 1,8-naphthalimide (NDI) chromophores. The stable configuration of that dimer was found with a help of density functional B3LYP/cc-pVDZ approach. The results of conformational analysis and the vibronic parameters derived from B3LYP/aug-cc-pVDZ and PBE0/aug-cc-pVDZ computations have led to the CD and absorption spectra, which are in very good agreement with the experimental spectra observed for the excitation energy corresponding to 1A1 → 2A1 and 1A1 → 1B1 overlapping transitions in the chromophore.