TABLE 4.
EXAFS simulation parameters
The following abbreviations are used: N, coordination number; R, interatomic distance; 2σ2, Debye-Waller factor; RF, error sum calculated for reduced distances of 1–3.5 Å (42); red, reduced, anaerobically prepared samples; xpr, aerobically prepared, X-ray photoreduced samples; ox, oxidized, aerobically prepared samples.
| Fe/Fe |
N (per metal)/R (Å)/2σ2 × 103 (Å2) |
RF | ||||
|---|---|---|---|---|---|---|
| Fe–N/O | Fe–N/O | Fe–C/N/O | Fe–C/N/O | Fe–Fe | ||
| % | ||||||
| Red | 1.90a/1.98/5b | 4.10a/2.15/5b | 1.82/2.86/2c | 3.75/3.11/5c | 1c/3.64/12 | 15.2 |
| Xpr | 2.34a/1.97/8b | 3.66a/2.11/8b | 1.62/2.54/2c | 2.58/3.05/5c | 1c/3.46/9 | 12.5 |
| Ox | 2.30a/1.91/6b | 3.70a/2.05/6b | 1.48/2.52/2c | 2.66/2.98/5c | 1c/3.43/7 | 15.5 |
| Mn/Fe | Mn–N/O | Mn–N/O | Mn–C/N/O | Mn–C/N/O | Mn–Fe | |
|---|---|---|---|---|---|---|
| Red | 0.38a/1.97/16b | 5.62a/2.19/16b | 1.64/2.58/2c | 0.81/3.27/5c | 1c/3.65/23 | 13.1 |
| Xpr | 1.17a/1.92/13b | 4.83a/2.14/13b | 0.62/2.63/2c | 1.32/3.11/5c | 1c/3.47/14 | 13.2 |
| Ox | 2.20a/1.90/11b | 3.80a/2.13/12b | 0.95/2.67/2c | 1.92/3.02/5c | 1c/3.51/8 | 17.8 |
a First sphere coordination numbers were coupled to yield a sum of 6.
b Debye-Waller factors were coupled to yield equal values for the two Fe/Mn–N/O shells.
c Fixed parameters.