“…Branching points are shown as circled numbers and are color coded to match their associated processes: ❶ represents the excited-state barrier partitioning fluorescence and isomerization; ❷ represents the photochemical funnel, which divides aborted from successful isomerization; and ❸ represents branching of strand dissociation and thermal relaxation. Abbreviations: C, noncovalently bound fluorescent protein complex with a cis chromophore in the ground electronic state; C’, noncovalently bound fluorescent protein complex with a trans chromophore in the ground electronic state; D, truncated protein containing a trans chromophore in the ground electronic state with the dissociated strand removed; P, dissociated strand (peptide); γ, population branching ratio at the photochemical funnel; E a,diss , energy barrier for thermal strand dissociation; E a,fwd , energy barrier in the excited-state to reach photochemical funnel; FC, Franck-Condon excitation from the ground- to the excited-state; k BC , rate constant for excited-state barrier crossing; k diss , rate constant for strand dissociation; k FI , rate constant for fluorescence; k IC , rate constant for nonradiative internal conversion without passing through the photochemical funnel; k th , rate constant for thermal relaxation from C’ to C. Figure adapted with permission from Reference 78.…”