mirror of https://github.com/abinit/abinit.git
40 lines
1.4 KiB
Markdown
40 lines
1.4 KiB
Markdown
---
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description: How to set parameters related to the phonon wavevectors (q-points) in DFPT calculations
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authors: FJ
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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 gives hints on how to set parameters related to the phonon wavevectors (q-points) in DFPT
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calculations with the ABINIT package.
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## Introduction
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Like the electronic wavefunctions, the collective atomic displacements that
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are eigenmodes of the corresponding periodic Hamiltonian can be characterized
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by a wavevector, denoted q-point.
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In ABINIT, DFPT calculations for one dataset are done for one specific
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q-point, that must be specified. In the simplest case, the user gives the
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corresponding q-point for each dataset, setting [[nqpt]]=1 and specifying the
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corresponding single [[qpt]]. However, very often, it is needed to run
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calculations for dozens or hundreds of q-points. Hence, the following
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mechanism has been set: the use can specify a set of q points, using input
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variables similar to the k-points, and then, for each dataset, the number of
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the q-point in the set is indicated thanks to [[iqpt]]. This applies to the
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generation of q-point grids as well as to q-point paths to produce phonon band
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structures.
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The input variables for specifying q-points in ANADDB are specified in
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[[topic:Phonons]] and [[topic:PhononBands]].
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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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