Frequency meshes

This page gives hints on how to define frequency meshes (on the imaginary and real axes) for MBPT calculations with the ABINIT package.

Copyright (C) 2016-2017 ABINIT group (MG)
Mentioned in   topic_GW,   topic_SelfEnergy,   topic_Susceptibility,   help_features#7.

Table of content:

 
 

1. Introduction.

In the contour deformation technique, and other cases, one has to define a set of frequencies on which different numerical operations will be performed (computation of susceptibility matrices, integration along the real+imaginary axes). In the present topic, the input variables connected to such definitions are gathered.

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2. Related lesson(s) of the tutorial.

  • The second lesson on GW (GW2) deals with the computation of the quasi-particle band structure of Aluminum, in the GW approximation (so, much better than the Kohn-Sham LDA band structure) without using the plasmon-pole model.


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    3. Related input variables.

    Basic input variables:

    ... freqremax [FREQuencies along the Real axis MAXimum]
    ... freqremin [FREQuencies along the Real axis MINimum]
    ... nfreqim [Number of FREQuencies along the IMaginary axis]
    ... nfreqmidm [Nth FREQuency Moment of the Imaginary part of the Dielectric Matrix]
    ... nfreqre [Number of FREQuencies along the REal axis]

    Input variables for experts:

    ... cd_customnimfrqs [Contour Deformation CUSTOM IMaginary FReQuencieS]
    ... cd_frqim_method [Contour Deformation FReQuency integration on IMaginary axis Method]
    ... cd_full_grid [Contour Deformation FULL GRID in complex plane]
    ... cd_halfway_freq [Contour Deformation tangent grid HALFWAY FREQuency]
    ... cd_imfrqs [Contour Deformation IMaginary FReQuencieS]
    ... cd_max_freq [Contour Deformation grid MAXimum FREQuency]
    ... cd_subset_freq [Contour Deformation grid calculate SUBSET of FREQuencies]
    ... gw_customnfreqsp [GW CUSTOM FREQuencies for SPectral function]
    ... gw_freqsp [GW SPectral FREQuencies]
    ... gw_frqim_inzgrid [GW Contour Deformation FReQuencies on IMaginary axis Inverse Z Grid]
    ... gw_frqre_inzgrid [GW Contour Deformation FReQuencies on REal axis Inverse Z Grid]
    ... gw_frqre_tangrid [GW Contour Deformation FReQencies on REal axis - Use Tangent Grid]


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