Figure 3.

RSVs resulting from SVD of time-dependent difference density maps plotted against the pump-probe time delays. Two significant vectors were fitted using two exponentials (corresponding to the relaxations of two intermediates) at pH 4 (A), pH 7 (B), and pH 9 (C). The first RSV is represented by circles, and the second is represented by squares. The relaxation times of the pR (τ₁) and pB (τ₂) states determined by the fit are marked by vertical dashed lines. Dashed line in panel A: At pH 7, the two RSVs were fitted by a sum of three exponentials, indicating a third intermediate (pB₂) at very low occupation with τ₁ = 71 ms (gray dashed vertical line).