The 2Ag− energies of all-trans-neurosporene and spheroidene as determined by fluorescence spectroscopy

The fluorescence spectra of neurosporene and spheroidene were recorded in order to determine their 2Ag− levels: each fluorescence spectrum was deconvoluted into two series of 1Bu+→1Ag− and 2Ag−→1Ag− vibronic transitions, and the energy of the 2Ag− (v=0) state was determined to be 15300 cm−1 in neurosporene and 14200 cm−1 in spheroidene. No temperature dependence of these energies was seen.