FEFF Variables

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Variables in the EXAFS and XANES formulae

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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.

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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)

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φc

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

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Feff

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

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φeff

The phase shift for each shell

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\mathcal{R}

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

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R

The distance to the central atom for each shell

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N

The mean number atoms in each shell

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σ2

The mean square fluctuation in R for each shell

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λ

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

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kf

The Fermi momentum at the average interstitial charge density

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p(r)

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

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Σ(E)

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

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μ(E)

The total absorption cross-section

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μ0(E)

The embedded atomic background absorption


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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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