ELPH_SELFEN_NW

ELPH_SELFEN_NW = integer
Default: ELPH_SELFEN_NW = 1 

Description: Number of energies to use when computing the phonon-induced electron self-energy.

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The electron self-energy, ${\mathrm{\Sigma }}_{n\mathbf{𝐤}}(\omega )$, depends on the frequency $\omega$ (or energy $\hslash \omega$). ELPH_SELFEN_NW controls the number and location of frequencies when computing the self-energy in the following way:

ELPH_SELFEN_NW > 0

The self-energy is computed at ELPH_SELFEN_NW equally spaced energies between ${\epsilon }_{n\mathbf{𝐤}}-\frac{1}{2}{E}^{\text{W}}$ and ${\epsilon }_{n\mathbf{𝐤}}+\frac{1}{2}{E}^{\text{W}}$. The interval is centered around each Kohn-Sham eigenvalue, ${\epsilon }_{n\mathbf{𝐤}}$, and its width, $E^{\text{W}}$, is controlled via ELPH_SELFEN_WRANGE. If ELPH_SELFEN_NW is an even number, it is automatically increased by one so that the middle-most energy always coincides with the Kohn-Sham eigenvalue.

ELPH_SELFEN_NW < 0

The self-energy is computed at |ELPH_SELFEN_NW| equally spaced energies between ${\epsilon }_{\mathbf{𝐤}}^{\text{min}}-\frac{1}{2}{E}^{\text{W}}$ and ${\epsilon }_{\mathbf{𝐤}}^{\text{max}}+\frac{1}{2}{E}^{\text{W}}$, where ${\epsilon }_{\mathbf{𝐤}}^{\text{min}}$ and ${\epsilon }_{\mathbf{𝐤}}^{\text{max}}$ are the minimum and maximum Kohn-Sham eigenvalues of the calculation, respectively. Once again, $E^{\text{W}}$ is controlled via ELPH_SELFEN_WRANGE and allows to extend the interval in both directions.