Table 2.
Final fits for the Fe K-edge EXAFS data over the k-range of 2–16 Å−1. Coordination number (N), interatomic distance (R, Å), mean-square thermal and static disorder in distance (σ2, Å2), and EXAFS threshold energy adjustment from 7030 eV (ΔE0, eV) were varied in the fits. Estimated errors are ± 0.02 Å in R, ± 0.0001 Å2 in σ2, and ± 20% in N. The goodness of fit, F, is defined as F = [Σk6(χexper. − χcalc.)2/Σk6(χexper.)2]0.5.
| FeMoco | FeVco | |||||
|---|---|---|---|---|---|---|
| No. | R (Å) | Σ2 (Å2) | No. | R (Å) | σ2 (Å2) | |
| Scatterer | ||||||
| Fe-S | 3 | 2.24 | 0.0038 | 2.5 | 2.23 | 0.0049 |
| Fe-Fe short | 3 | 2.64 | 0.0042 | 2.5 | 2.63 | 0.0061 |
| Fe-O | 0.5 | 1.96 | 0.0048 | 1.5 | 1.97 | 0.0067 |
| Fe-C | - | - | - | 1.5 | 3.07 | 0.0015 |
| Fe-Mo | 0.5 | 2.68 | 0.0016 | - | - | - |
| Fe-Fe | 0.5 | 2.87 | 0.0028 | - | - | - |
| Fe-(Fe/V) | - | - | - | 1 | 2.88 | 0.0050 |
| Fe-Fe long | 1 | 3.70 | 0.0022 | 1 | 3.69 | 0.0051 |
| ΔE0 (eV) | −10.6 | −13.5 | ||||
| Weighted F | 0.121 | 0.155 | ||||