Questions tagged [dielectric-constants]

Questions on dielectric constants as they relate to materials modeling.

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Optical proprieties with Quantum espresso

I am a beginner in Quantum Espresso, and I want to calculate optical properties. When I calculate the dielectric functions, it gives me four output files. I don't know which files correspond to the ...
SOELHADFI's user avatar
  • 329
2 votes
0 answers

Query about optical data extraction using Vaspkit

Recently I tried to extract the optical absorption data using Vaspkit (vaspkit.1.3.0/vaspkit.1.3.5]). I performed the optical calculations of one 2d system along with SOC using VASP. While extracting ...
Poonam Sharma's user avatar
4 votes
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How can we calculate transverse and longitudinal optical phonon frequencies

Could you please help me to calculate the "transverse and longitudinal optical phonon frequencies" from phonopy+vasp output files? These parameters will help me to calculate the high-...
rekha's user avatar
  • 41
6 votes
1 answer

Do I have to use the same functional for dielectric function calculations, as the one used for relaxing the structure?

This is a general question regarding the practices of doing optical calculations and the role of the ionic contribution to the dielectric function (with heavy reference to VASP). Based on VASP's ...
CW Tan's user avatar
  • 1,014
7 votes
2 answers

Why is there a large discrepancy between calculated frequency dependent dielectric function and experimental measurement?

I am calculating the frequency dependent dielectric function of $\ce{SiC}$ using VASP. After a geometry optimization, the INCAR file below is used for the ...
Achintha Ihalage's user avatar
12 votes
2 answers

Algorithm for calculating dielectric constant of water TIP3P

I am running a NVT TIP3P simulation of water with 125 molecules of water in a 16-by-16-16 angstrom box with periodic boundary conditions on LAMMPS, with a time-step of 1 fs for 10 ps. Once the ...
megamence's user avatar
  • 4,141
15 votes
1 answer

VASP Dielectric constants: What potential to use?

I've simulated the dielectric constants using the LEPSILON = .TRUE. tag and the PBE GPAW potentials. A collegue mentioned that for accurate results norm conserving pseudo-potentials are the way to go. ...
CKl's user avatar
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17 votes
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Is there a way to obtain solution-phase dielectric constants?

I wish to calculate solution-phase dielectric constants (required for a Monte-Carlo model) for CoCl$_2$ and TaS$_2$ dissolved in DMF. Is it possible to estimate these constants from the solid-state ...
nathanielng's user avatar