Figure 7.

⁵⁷Fe Mössbauer spectra (vertical bars) for RFQ of FDP_red mixed with ∼3 equiv of NO per active site at ∼15 °C and quenched at the times listed near each spectrum. The spectra were recorded at (A) 80 K in zero magnetic field or (B) 4 K in a magnetic field of 45 mT applied parallel to the γ-ray direction. The colored traces are simulations of species assigned to Fe^IIFe^II (blue), Fe^II (green) {FeNO}⁷ (red) of Fe^II{FeNO}⁷, L (light blue), H (pink), and diferric (purple), respectively, using the parameters listed in Table 1 and percent compositions listed in Table 3; black traces are the sums of the simulated species spectra. Concentrations immediately after mixing: 500 μM FDP_red and 1500 μM NO.