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<p>Hi Zac,</p>
<p>You might look at a Python package called PDielec on GitHub (
<a class="moz-txt-link-freetext" href="https://github.com/JohnKendrick/PDielec">https://github.com/JohnKendrick/PDielec</a> ). It has the capability
of calculating the IR spectrum (reflectance, absorption and
transmission) for single crystals either as thick slabs or thin
films. For powders it uses an effective medium theory approach to
calculating the frequency dependent permittivity, from which the
spectrum can be determined. It can also be used to view the
phonon mode molecular and atomistic motion and provides some basic
break-down of the energy in each mode in terms of internal and
external modes.</p>
<p>It has an interface to several packages, including Quantum
Espresso, VASP, CRYSTAL, AbInit and CASTEP.<br>
</p>
<p>John<br>
</p>
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<div class="moz-header-display-name" style="display:inline;">Subject:
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[QE-users] IR calculation for oriented single crystal</td>
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<div class="moz-header-display-name" style="display:inline;">From:
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Zack Gainsforth <a class="moz-txt-link-rfc2396E" href="mailto:zackg@berkeley.edu"><zackg@berkeley.edu></a></td>
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<div class="moz-header-display-name" style="display:inline;">Date:
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18/03/2022, 05:23</td>
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<div class="moz-header-display-name" style="display:inline;">To:
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Quantum ESPRESSO users Forum
<a class="moz-txt-link-rfc2396E" href="mailto:users@lists.quantum-espresso.org"><users@lists.quantum-espresso.org></a></td>
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<pre class="moz-quote-pre" wrap="">Hi All,
I have set up a calculation using pw.x -> ph.x -> dynmat.x successfully and plotted myself an IR spectrum. The match to the experimental spectrum is good. However, this is an IR spectrum assuming a powder where the photons are exciting all the modes. I’d now like to calculate the spectrum for a single crystal and specify the electric vector of the photon relative to the crystal. It should preferentially excite certain modes.
Is there a straightforward way to do this using ph.x + dynmat.x? Or perhaps a way to read/print the dipole vectors for each mode so I can dot it with my photon’s e-field? Or another way of thinking about this which is more efficient? (Maybe I missed something in the documentation!)
Thanks,
Zack
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