mirror of https://github.com/abinit/abinit.git
46 lines
2.2 KiB
Markdown
46 lines
2.2 KiB
Markdown
---
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description: How to perform macroscopic averages of the densities and potentials
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authors: XG
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---
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<!--- This is the source file for this topics. Can be edited. -->
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This page explains how to perform macroscopic averages of the densities and potentials with the ABINIT package.
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## Introduction
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The MACROAVE program implements the macroscopic average technique,
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introduced by A. Baldereschi et al [[cite:Baldereschi1988]].
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This powerful method relates microscopic quantities, typical outputs of first-principles codes,
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with macroscopic magnitudes, needed to perform electrostatic analysis.
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Within this methodology, one is able to wash out all the
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wiggles of the rapidly-varying functions of position (resembling the underlying atomic structure)
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of the microscopic quantities,
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blowing up only the macroscopic features.
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It can be used to compute band offsets, work functions, effective
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charges, and high frequency dielectric constants, among others.
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See also [[cite:Colombo1991]] as well as [[cite:Shaltaf2008]], the latter for an application using
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the MACROAVE program delivered with ABINIT, see Fig.1 .
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To use the MACROAVE program, prepare an input file named "macroave.in" . No other name is admitted.
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The examples below should be renamed "macroave.in".
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Issue simply "macroave", without any argument. Two files will be generated, whose names
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are constructed from the name of the density or potential file in the third line of the input macroave.in file,
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let us take t41_DEN as an example.
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The first one will have been appended with .PAV , which is an abbreviation for Planar AVerage.
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Only the x-y average has been done to generate this file. From t41_DEN, one generates t41_DEN.PAV.
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The second one will have been appended with .MAV , which is an abbreviation for Macroscopic AVerage.
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The x-y average has been followed by the macroscopic average to generate this file. From t41_DEN, one generates t41_DEN.MAV.
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Note that the planar average is always done on the x-y plane, and the macroscopic average in the z direction.
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Note that macroave works in reduced coordinates, so it will not encounter problems with non-orthogonal primitive vectors.
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## Related Input Variables
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{{ related_variables }}
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## Selected Input Files
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{{ selected_input_files }}
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