mirror of https://gitlab.com/QEF/q-e.git
35 lines
1.7 KiB
Plaintext
35 lines
1.7 KiB
Plaintext
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This example illustrates how to use pw.x and ph.x to calculate phonon
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frequencies of LiCoO2 with Hubbard U on Co 3d states. Note, the
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phonon frequencies and other quantities are not converged in this
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example.
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The calculation proceeds as follows (for the meaning of the cited input
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variables see the appropriate INPUT_* file)
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1) make a self-consistent calculation (input=LiCoO2.scf.in,
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output=LiCoO2.scf.out)
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2) make a phonon calculation for gamma point (input=LiCoO2.phG.in,
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output=LiCoO2.phG.out). Note that outdir and prefix have the same
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values as in the input for scf calculation. Note that the q-point
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(the Gamma point in this case) is read after the namelist inputph.
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Dynamical matrix will be saved for further analysis in fildyn (whose
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default name is 'matdyn', here overwritten to LiCoO2.dynG).
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Note that epsil=.true. and the response to an electric field and
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the dielectric constant are also calculated.
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The Gamma point is the ONLY one for which the phonon code can be run
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directly after the scf run (provided save file was defined).
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For all other points in the BZ a non-scf preparatory run is needed,
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as it is shown here for q = (0, 0, 1/4).
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3) make a phonon calculation for q = (0, 0, 1/4) (input=LiCoO2.phq.in,
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output=LiCoO2.phq.in). Note that the q-point is read after the namelist
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&inputph. Dynamical matrices will be saved for further analysis in fildyn
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(whose default name is 'matdyn', here overwritten to LiCoO2.dynq).
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The fildyn file contains the dynamical matrices for q-points that
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are equivalent by symmetry to the q-point given in input, therefore
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when calculating phonons in the whole BZ the code needs to be run
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only on inequivalent points.
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