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13 votes

Is there a way to obtain solution-phase dielectric constants?

It's possible to estimate solution-phase dielectric constant from a molecular dynamics simulation using this formula: $$\epsilon_{r} = 1 + \frac{4\pi}{3Vk_{B}T}(\langle \mathbf{P}^{2} \rangle - \...
Mithridates the Great's user avatar
10 votes
Accepted

Optical proprieties with Quantum espresso

There will be 4 output files in total for an epsilon.x run. These are: ...
Abdul Muhaymin -Free Palestine's user avatar
6 votes
Accepted

Dielectric tensor εij (total)

The dielectric tensor can be split in the ionic $(ϵ_{ij}^{0})$ and electronic $(ϵ_{ij}^{∞})$ contributions:$$ϵ_{ij}=ϵ_{ij}^{0}+ϵ_{ij}^{∞}$$ According to VASP documentation. To obtain the ionic ...
Jaafar Mehrez's user avatar
6 votes

VASP Dielectric constants: What potential to use?

I don't think there is a consensus of norm conserving PP being more accurate. There are some references I am aware of which have calculated dielectric tensor using NC-PP, but without justification ...
gogo's user avatar
  • 1,247
5 votes

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

Wait, those are two very different resonances. The one at 150-200 nm is obviously of electronic origin, whereas the one at about 12 microns is related to phonon modes. There is quite a lot of ...
sleepy's user avatar
  • 291
5 votes
Accepted

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

It's not obvious to me that you are doing anything wrong in your calculation. Your result for the crossover energy seems consistent with the literature, e.g. Theodorou et al. (1999) and Petalas et al. ...
Anyon's user avatar
  • 4,741
4 votes

Algorithm for calculating dielectric constant of water TIP3P

Aren't you missing the volume in the denominator? And the order of the norm and average is probably off in the second term. The original equation should be $$ \epsilon = 1 + \frac{\langle |\mathbf{M}|...
Jonatan Öström's user avatar
4 votes

Algorithm for calculating dielectric constant of water TIP3P

Molecules will not be on both sides of the box at once because this is explicitly prevented by most good MD packages. You can calculate distances which take into consideration the PBC. For example, ...
Cody Aldaz's user avatar
  • 8,017
3 votes
Accepted

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

After 7 days of the bounty period not attracting any answers, I'll answer this question to the best of my abilities. General considerations Geometry optimization with one method, and properties with ...
Nike Dattani - No Free Time's user avatar

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