I have the calculated real and imaginary parts of dielectric function and energy loss function using epsilon.x in quantum espresso. Now I do not know how to find the above quantities using quantum espresso.
Thanks in advance for your help and cooperation.
If you have calculated real and imaginary parts of dielectric function then you can calculate refractive index, extinction coefficient, reflectivity, optical conductivity and absorption coefficient. I mean calculate manually.
Rashid Khan I am trying to calculate the dielectric function using epsilon.x, but i am always getting USPP not implemented error. Can you help?
Dear Mayank Dotiyal ,
The calculation of optical properties in QE is implemented for NCPP. It is true that the calculation for USPP is likely not implemented yet.
I am also looking for the same problem..can you help me if you got your answer how to calculate these properties using quantum espresso..? @Rashid Khan
Dear Vaishali Nimbewal,
You can calculate it manually by using the real and imaginary parts of the dielectric function. Please review the below article for further details:
"Article Effect of manganese on electronic and optical properties of ...
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Thank you dear Rashid Khan,
Ok so we calculate img and real parts of dielectric function using epsilon.x and then other properties manually. But then how you plot the refractive index ,absorption spectra and conductivity graph?Do you calculate it manually at every point? Please help.Thank you in advance.
Dear Vaishali Nimbewal,
Yes, use epsilon.x to find out the real and imaginary part of the dielectric function and calculate other quantities manually using the following equations (please see the attached screenshot).
Rashid Khan Shibghatullah Muhammady how can i plot refractive index graph. which value i have to from output file? help me out
From ε1 and ε2 from the output files, use the formula to find n1 and n2. Then, we can plot n1 and n2.
Shibghatullah Muhammady Thank you . can you explain me exactly . In imaginary file 4 columns are there energy grid, epsi_x epsi_y epsi_z. then how can i calculate refractive index from it. I know formula is there. I don't exactly get how to calculate
Aiswarya Priyambada ,
we can obtain nx, ny, and nz from it. We can apply epsilon of each direction to obtain refractive index for each direction as well. The formula is shown by Rashid Khan above.
Shibghatullah Muhammady Is there any command to plot refractive index using the formula?
Aiswarya Priyambada, use the above equation for the refractive index which I already shared (please see my aforementioned answer). You can follow the below steps:
1) If you are using a cubic system then take the average of the real part of the dielectric function e1x, e1y, and e1z, and similarly, take the average of the imaginary part of the dielectric function for isotropic material.
2. Use the average value of the real and imaginary part of the dielectric function to find the average value of the refractive index.
3. Draw the graph between photon energy vs refractive index (for more detail please review my research article).
4. You can also calculate individually refractive index along x, y and z-axes.
Photon charging can provide some new understanding.
The key evidence for light waves is the Young’s double-slit interference experiment. After the discovery of the double-slit interference experiment of particles (electrons, etc.), the conclusion of light waves can no longer be established. "Wave-particle duality" denies light as particles because of the wave phenomenon, but recognizes the wave nature of particles. It is better understood that light particles have wave phenomena. Of course, light particle behavior and wave mechanism need new understanding.
https://book4you.org/book/18269199/bf2351
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