Structure of the input data: =============================================================================== &inputgw ... / Frequencies ... / K_points ... / ======================================================================== NAMELIST: &inputgw +-------------------------------------------------------------------- Variable: do_coulomb, do_green, do_sigma_exx, do_sigma_c, do_sigma_matel. Type: LOGICAL Default: .false. Description: control variables for determining which aspects of the calculation are to be run. In order: perform calculation of screened coulomb interaction, the Green's function, exact exchange component of the interaction, the correlation energy, and the matrix elements of the single particle states with the various operators. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: prefix Type: CHARACTER Default: 'sgw' Description: prepended to input/output filenames: prefix.wfc, prefix.rho, etc. Must be the same as the underlying scf calculation. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: use_symm Type: LOGICAL Default: .TRUE. Description: Logical variable to determine whether or not symmetry is used to reduced the number of independent solutions of the Sternheimer equation required. use_symm only calculates electronic response to unique G vectors. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: do_imag Type: LOGICAL Default: .false. Description: Performs calculation along imaginary axis. Both the Green's function and the screened Coulomb interaction are calculated along the imaginary, the convolution is performed using a Gauss-Legendre grid. Significant saving in time and memory compared to real frequency integration. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: ecutsco, ecutsex Type: REAL(DP) Default: 5 Ry. Description: Planewave energy cutoffs for the (co)rrelation energy and the (ex)change energy. Typically a higher cutoff for the exchange energy is required. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: godbyneeds, padecont, freq_gl Type: LOGICAL Default: godbyneeds Description: Choice of screening model for the screened Coulomb interaction. The Godby-Needs plasmon pole model requires fitting the dielectric function to two points on the imaginary axis, typically at 0, and i\omega_{p} where \omega_{p} is the classical plasmon frequency. The padecont chooses analytic continuation of the frequency dependence. freq_gl only calculates the screened Coulomb interaction at the points required by the Gauss-Legendre grid. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: maxter_green Type: INTEGER Default: 200 Description: Maximum number of conjugate gradient minimization steps. A warning will be issued if the linear system does not converge for multishift. In this case you may have to raise maxter_green or abandon the multishift linear system solver. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: nbnd_sig Type: INTEGER Default: number of occupied bands + 4 Description: Number of bands included in the final ouput. Typically one is interested in the selfenergy, quasiparticle corrections, and self-energy operator for the states around the band gap or Fermi energy. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: Type: Default: Description: +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: Type: Default: Description: +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: wcoulmax Type: REAL Default: 80 eV Description: The cutoff in eV of the frequency dependence of the Screened Coulomb interaction. +-------------------------------------------------------------------- +-------------------------------------------------------------------- Variable: wsigmamin, wsigmamax, deltaw Type: REAL Default: 0.0 eV, 20.0 eV, 5.0 eV Description: The minimum and maximum, and spacing, of the frequency points for the selfenergy. In the case of do_imag, these are the frequency points along the imaginary axis which are fitted to perform the analytic continuation. For real frequencies a much finer grid would be required. +-------------------------------------------------------------------- FREQUENCIES Line of input: nfs w(1) w(2) .... w(1) w(2) DESCRIPTION OF ITEMS: +-------------------------------------------------------------------- Variable : nfs Type: INTEGER Description: Number of frequency points in the calculation of W(iw). If the Godby-Needs plasmon-pole model is used only two frequency points are required. For the analytic continuation more points are required +-------------------------------------------------------------------- K_Points ======================================================================== Line of input: nqs xq(1) xq(2) xq(3) DESCRIPTION OF ITEMS: +-------------------------------------------------------------------- Variable : nqs Type: INTEGER Description: number of q points Variables: xq(1) xq(2) xq(3) Type: REAL Description: The electric field wavevectors, or the point at which Sigma_{q} is calculated in units of 2pi/a0 (a0 = lattice parameter). +-------------------------------------------------------------------- ===End of line-of-input=================================================