Variables: Difference between revisions

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<span id="NGBlkX">  <!--single variable anchor-->
<span id="NGBlkX">  <!--single variable anchor-->
{{var1|NGBlkXd|RL|Number of G-vectors in the screening.|This determines the size of the dielectric matrix in G-space. Needed for inclusion of local field effects. It should be much smaller than the number of G-vectors needed to expand the wavefunctions. It needs careful convergence.  }}
{{var1|NGBlkXd|RL|Number of G-vectors in the screening.|Determines the size of the dielectric matrix in G-space. Needed for inclusion of local field effects. It should be much smaller than the number of G-vectors needed to expand the wavefunctions. It needs careful convergence.  }}
</span>
<span id="ETStpsX">  <!--single variable anchor-->
{{var1|ETStpsX|integer|Number of energy steps.|Determines the number of steps in energy the response function/spectrum is computed for in the desired range defined by EnRngeX. Has little effect on memory or time. }}
</span>
 
<span id="EnRngeX">  <!--single variable anchor-->
{{var2|EnRngeXd/Xs|Energy|Energy range the spectrum is calculated across.|Energy range }}
</span>
</span>



Revision as of 16:09, 27 March 2017

Units

  • Energy = RL (number of G-vectors), Ha, mHa (Hartree atomic units), Ry (Rydberg atomic units), eV (electron volts)
  • Blah = dsfa

Initialization

Variable: MaxGvecs (Units: Energy) Meaning: Number of G-vectors in screening
Tip: This determines the size of the dielectric matrix in G-space. Needed for inclusion of local field effects. It should be much smaller than the number of G-vectors needed to expand the wavefunctions. It needs careful convergence.

Optics

Variable: FFTGvecs (Units: RL) Meaning: Number of G-vectors used in expanding the wavefunctions and in FFT transforms
Tip: It needs careful convergence. Determines the memory needed.

Variable: NGBlkXd (Units: RL) Meaning: Number of G-vectors in the screening.
Tip: Determines the size of the dielectric matrix in G-space. Needed for inclusion of local field effects. It should be much smaller than the number of G-vectors needed to expand the wavefunctions. It needs careful convergence.

Variable: ETStpsX (Units: integer) Meaning: Number of energy steps.
Tip: Determines the number of steps in energy the response function/spectrum is computed for in the desired range defined by EnRngeX. Has little effect on memory or time.

EnRngeXd/Xs (Units: Energy, Format: Energy range the spectrum is calculated across.)
Meaning: Energy range
Tip: {{{5}}}

GW

Variable: EXXRLvcs (Units: RL) Meaning: Number of G-vectors used in the sum of the exchange self-energy Sx.
Tip: It needs careful convergence: not particularly time consuming, large values can be used to ensure convergence.

Variable: QPkrange (Units: Integers) Meaning: First and last Indexes of kpoints and bands the slef energy correction is calculated
Tip: If interested in non consecutive kpoints or bands multiple rows can be also considered