“…If normal forward photochemistry is to occur, this state reduces X in 100-200 ps [2,3] but if this is blocked by the prior chemical reduction [4] or removal [5] of X, the transient state has a lifetime of nanoseconds before decaying (t½ ~, 10 ns at 300°K; "~ 30 ns at 80°K [4,6]). It has been suggested [7] that [-" has some spectrophotomeric characteristics of reduced bacteriopheophytin (BPh-").…”