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

[Iurii TIMROV]

Dear Xavier,


Check the output file generated using the turbo_spectrum.x program. If you perform the calculation using ipol = 4 you will find the following:


chi_i_j: dipole polarizability tensor  in units of e^2*a_0^2/energy


S: oscillator strength in units of 1/energy


S(\hbar \omega) = 2m/( 3 \pi e^2 \hbar)  \omega sum_j chi_j_j


For more details please check this paper: https://www.sciencedirect.com/science/article/pii/S0010465511001512


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: José Xavier <jxln_karate at yahoo.com.br>
Sent: Sunday, May 28, 2023 1:12:35 AM
To: Quantum ESPRESSO Users Forum; Iurii TIMROV
Subject: Re: Doubt about Hands-on QE summer school TD-DFT exercise (day 3)

Dear Dr. Timrov,

Thank you again. You have helped me a lot.
I'll read the references you suggested.

In the hands-on, the spectrum (absorption, I believe) is plotted just using the ômega (in eV) and the imaginary dielectric constant. Why? Isn't it necessary another data?

Besides, converting the ômega for eV, which unit should I use in the absorption plot (Y axis)?


Thanks for your help

Xavier
Universidade Federal do Rio Grande do Norte


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