with a polarizable continuum model for incorporating the bulk effect of the surrounding
environment is used to estimate the excitation energies for the phytochromobilin
chromophore of plant phytochrome. The TDDFT results reproduce well the experimental
values of the absorption maxima and those of the ratio of the spectroscopic bands (Q band
over the Soret band or Q/S index). Our results suggest that the phytochromobilin within the …