The electronic structure was computed using the pQED scheme (see Sec.3.1) using the Jaynes-Cummings Hamiltonian (i.e., no counter-rotating terms or dipole self-energy) with a minimal basis of |S 0 , 0⟩, |S 0 , 1⟩, and |S 1 , 0⟩. Here the electronic structure was computed at the semi-empirical AM1 level 255 coupled with the floating occupation molecular orbital configuration interaction (FOMO-CI) scheme for the calculation of the lowest singlet excited state S 1 .