FEFF Variables

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Variables in the EXAFS and XANES formulae

k

The wave number in units of \AA\!^{-1}. k = \sqrt{E-E_f} where E \,\! is energy and E_f \,\! is the Fermi level computed from electron gas theory at the average interstitial charge density.

χ(k)

\chi(k) = S^2_0 \mathcal{R}\sum_{shells}\frac{N F_{eff}}{k R^2}\exp(-2r/\lambda)\sin(2kR+\phi_{eff}+\phi_c)\exp(-2k^2\sigma^2)

φc

The total central atom phase shift, \phi_c=2\delta_{l,c}-l\pi \,\!

Feff

The effective curved-wave backscattering amplitude in the EXAFS formula for each shell.

φeff

The phase shift for each shell

\mathcal{R}

The total central atom loss factor, \mathcal{R}=\exp(-2\mbox{Im}(\delta_c))

R

The distance to the central atom for each shell

N

The mean number atoms in each shell

σ2

The mean square fluctuation in R for each shell

λ

The mean free path in Å, \lambda = 1/|\mbox{Im} p| \,\!

kf

The Fermi momentum at the average interstitial charge density

p(r)

The local momentum, p^2(r)= k^2 + k^2_f(r)+\Sigma-\Sigma_f

Σ(E)

The energy dependent self energy at energy E, \Sigma_f \,\! is the self energy at the Fermi energy.

μ(E)

The total absorption cross-section

μ0(E)

The embedded atomic background absorption



FEFF Input and Output Files

Descriptions of output files

  1. Intermediate output files
  2. Diagnostic files
  3. Main output data
  4. Variables in the EXAFS and XANES formulae

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