[QE-users] [SPAM] Doubt about Hands-on QE summer school TD-DFT exercise (day 3)

[Iurii TIMROV]

> 1- It is selected the ipol=1 in Lanczos file. The manual shows it as XX direction. Is it the 100 or 001 direction of the polarized light? I read a paper in which it is considered the 100, but in other forums, it was said that it is 001...

As far as I understand, it is 100

> 2- Why is the script used to plot the spectrum set to multiply column 4 (imaginary dielectric) by 0.000276? I understood that the ($2)*13.6 was set to convert Ry to eV, but I can't even guess the reason for the 0.000276...

The intensity is in arbitrary units. This factor was used just to match the arbitrary units from two codes (Lanczos and Davidson).

HTH

Iurii


--
Dr. Iurii TIMROV
Senior Research Scientist
Theory and Simulation of Materials (THEOS)
Swiss Federal Institute of Technology Lausanne (EPFL)
CH-1015 Lausanne, Switzerland
+41 21 69 34 881
http://people.epfl.ch/265334
________________________________
From: users <users-bounces at lists.quantum-espresso.org> on behalf of José Xavier via users <users at lists.quantum-espresso.org>
Sent: Thursday, May 18, 2023 11:08:21 PM
To: Quantum ESPRESSO Users Forum
Subject: [QE-users] [SPAM] Doubt about Hands-on QE summer school TD-DFT exercise (day 3)

Dear QE users,

I'm new to optical properties calculation, and I want to ask If anyone could help me with two doubts about the Hands-on exercises in the https://gitlab.com/QEF/material-for-ljubljana-qe-summer-school/-/blob/master/Day-3/example6/

1- It is selected the ipol=1 in Lanczos file. The manual shows it as XX direction. Is it the 100 or 001 direction of the polarized light? I read a paper in which it is considered the 100, but in other forums, it was said that it is 001...

2- Why is the script used to plot the spectrum set to multiply column 4 (imaginary dielectric) by 0.000276? I understood that the ($2)*13.6 was set to convert Ry to eV, but I can't even guess the reason for the 0.000276...

Thanks for your help

Xavier
Universidade Federal do Rio Grande do Norte
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