In photosynthetic proteins, pigments at a higher energy level funnel excitation energy to pigments at a lower energy level. Specifically, in Photosystem II (PSII), energy is transferred downhill to the reaction center (RC), where water splitting occurs. However, the lowest-energy state in PSII is not the RC, but the F695 state, which can be observed using low-temperature spectroscopy. This lowest-energy state is typically assi...