Photoexcitation free energies of solvated molecules from raw absorption spectra: Can a Jarzynski-like equality be employed?

► Molecular photoexcitation is seen as a process driven by the incident radiation. ► Jarzynski equality is adopted to define/evaluate the photoexcitation free energy. ► Photoexcitation free energy can be experimentally obtained from absorption spectra. ► Analysis on model cases supports the proposed perspective.