A simple method for calibration of hybrid exchange–correlation functionals for precise calculations of fluorescence wavelengths of dibenzoylmethanatoboron difluoride exciplexes with benzene, alkylbenzenes and pyridine

A simple approach to precise calculation of fluorescence wavelengths of charge-transfer exciplexes formed by dibenzoylmethanatoboron difluoride (DBMBF₂) with benzene, alkylbenzenes and pyridine by varying the percentage of Hartree–Fock exchange energy (HFX) in the hybrid BHHLYP exchange–correlation functional is proposed. A correlation revealed between the optimal HFX parameter and the degree of charge transfer (CT) in the exciplexes provides a basis for the pre-assessment of the required HFX parameter in the BHHLYP functional from the calculated CT value in an exciplex of interest.