Table 1.

One- and two-shell simulations of Mn EXAFS Fourier peak II from the S1, S2, S3, and S0 states

FitSampleShellR, ÅNσ2 (× 103), Å2Φ (× 103)ε2 (× 105)
One shell
1S1Mn–Mn2.731.11.70.200.10
2S2Mn–Mn2.741.11.60.220.10
3S3Mn–Mn2.761.43.30.310.15
4S0Mn–Mn2.731.32.00.300.16
Two shells
5S3Mn–Mn2.751.11.0*0.230.11
Mn–Mn2.880.51.0*
6S0Mn–Mn2.731.11.0*0.280.14
Mn–Mn2.850.31.0*
  • R is the Mn–Mn distance. S02, an amplitude reduction factor (see SI Text, Eq. 1), was set to 0.85. Range-extended EXAFS methodology can distinguish two Mn–Mn distances at ≈2.7 and ≈2.8 Å contributing to peak II in the S1 and S2 states (16, 17). Peak II in the S1 and S2 states can only be fit to one shell of Mn–Mn interactions at the resolution of conventional EXAFS. However, a two-shell fit is favored for the S0 and S3 states as indicated by an increased Debye–Waller factor for the one-shell fit. Φ and ε2 are the goodness-of-fit parameters (see SI Text).

  • *Parameter was fixed.