Table 2.
Final EXAFS fit results over a k range of 2–16 Å−1. The variables are coordination number, N; interatomic distance, R; mean-square thermal and static deviation, σ2; and the shift in the threshold energy from 20025 eV, ΔE0. The estimated uncertainties in R, σ2, and N are ± 0.02 Å, ± 0.0001 Å 2, and ± 20%, respectively. The goodness of fit, F, is defined as F = [Σk6(χexptl. − χcalcd.)2/Σk6(χexptl.)2]0.5. Data of NifEN“FeMoco” were taken from our earlier report (18).
| NifEN“FeMo” | NifEN“FeMoco” | |||||
|---|---|---|---|---|---|---|
| N | R(Å) | σ2(Å2) | N | R(Å) | σ2(Å2) | |
| Scatterer | ||||||
| Mo-O short | - | - | - | 1 | 2.12 | 0.0055 |
| Mo-O long | 3 | 2.24 | 0.0030 | 2 | 2.24 | 0.0012 |
| Mo-S | 3 | 2.33 | 0.0080 | 3 | 2.37 | 0.0059 |
| Mo-Fe short | 2 | 2.73 | 0.0042 | 2 | 2.71 | 0.0029 |
| Mo-Fe long | 1 | 2.92 | 0.0053 | 1 | 2.90 | 0.0058 |
| ΔE0 (eV) | −8.8 | −8.9 | ||||
| Weighted F | 0.301 | 0.150 | ||||