Optical Properties: DFT, Pseudopotential, Plasma Frequency, Transmission

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    Optical Properties
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Discussion Overview

The discussion revolves around the optical properties of a compound, specifically focusing on the determination of plasma frequency and the relationship between peaks in the loss function and transmission characteristics. The context includes theoretical calculations using Density Functional Theory (DFT) and pseudopotentials.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant questions whether only the highest peak in the loss function determines the plasma frequency or if all peaks correspond to different densities of valence electrons.
  • Another participant seeks clarification on whether the peaks in the dielectric function (ε1) indicate maximum transmission.
  • A participant describes their calculations for the optical properties of SrS, noting discrepancies between the plasma energy calculated from electron density and that obtained from the highest peak in the loss function.
  • There is a suggestion that the peaks in the loss function may represent transition energies, with a need for further guidance on the interpretation of these results.
  • A later reply corrects a terminology error from "picks" to "peaks" in the context of discussing the loss function.

Areas of Agreement / Disagreement

Participants express uncertainty regarding the interpretation of peaks in the loss function and their relationship to plasma frequency and transmission. No consensus is reached on these points, and multiple views remain present.

Contextual Notes

Participants mention specific calculations and assumptions regarding the density of valence electrons and the use of pseudopotentials, but these details are not fully resolved or agreed upon.

bahaar
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Hello

1- I calculate optical properties of a pure compound in framework of DFT with pseudopotential by software. I get several picks in loss function. Does only the highest , determine plasma frequency or all of them with different density of valence electrons?

2-can we conclude the picks of the ε1 always show the maximum of transmisson?

Thanks
 
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Hi
Perhaps i should clear more my question. Please guide me.
I calculate the optical properties of SrS compound.I have two question:
1. In the loss function, there are several picks. I want determine plasma frequensy. Does only the highest pick show position of plasma freqeuncy and other picks show transition energies? can we tell the other picks are plasma frequencies correspond to different densities of valence electrons?
2. I used HGH pseudopotentials. 10 electrons of [38]Sr and 6 electrons of [16]S are used as valences electrons in these psedopotentials. So i plus these two values (10+6=16) and divide to two atoms's volume (1/4 volume of cell) and used the

wp =√(ne20m) to get plasma energy, but this value is 7-8ev less than plasma energy that achieved from highest pick in loss function.These means i must use approximately 30 electrons to calcuate n=density of valence electrons . The plasma energy of highest pick are correspond approximately to other theory results in different papers. please help me to solve it.
Thanks a lot.
 
You are talking about peaks (not picks)?
Maybe this article is helpful:
http://www.sciencedirect.com/science/article/pii/0038109882905555
 
Hi.
Yes my means was peak. It is really embarrassing:blushing:.
Thanks a lot for your reply:biggrin:.
 

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