Questions tagged [optical-properties]

Questions about optical properties.

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How to select NBANDSO and NBANDSV and NBANDS values in BSE GW calculation in VASP

I am not aware of how to select NBANDSO and NBANDSV and NBANDS values in the 5th step while doing the BSE calculations. Please suggest.
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5 votes
0 answers
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Optical Property calculation in VASP using HSE [closed]

I have calculated frequency-dependent dielectric constant in VASP using PBE exchange-correlation functional, within the framework of Independent particle approximation (with RPA). I want to perform ...
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4 votes
0 answers
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Evaluating Absorption coefficient using VASPKIT for nanostructures

I was planning to use VASPKIT in order to determine the Linear optical properties of my nanostructure. But upon running vaspkit, I do not see an option for 0D materials but only for 2D and Bulk. Is ...
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2 answers
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Optical spectra beyond electric dipole approximation

I'm wondering what are the typical examples (experiments) for magnetic dipole transitions and electric quadrupole transitions in crystals?
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4 votes
1 answer
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Optical properties without LOPTICS tag

I have performed some calculations for a 2D-monolayer using VASP. I run DOS calculations without LOPTICS = .TRUE. I found that ...
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8 votes
2 answers
130 views

Can the color of gold metal be reproduced by modeling only the conduction electron band structure, or do atomic absorption lines contribute?

@JohnCuster's answer to Why is gold golden? is based on the band structure of the delocalized conduction electrons in gold, whereas other answers there tend to support the "Gold is gold due to ...
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7 votes
2 answers
215 views

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 ...
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4 votes
1 answer
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Optical anisotropy from first-principles

I am interested in the theoretical study of optical anisotropy (birefringence, dichroism etc.) of different materials. I have seen DFT works studying optical anisotropy from the calculation of ...
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8 votes
3 answers
590 views

Why can't we change the spin angular momentum of electrons with an external optical field?

I have read this paper many times: Coupled Spin and Valley Physics in Monolayers of MoS2 and Other Group-VI Dichalcogenides. Interestingly, this paper is also discussed many times in this community, ...
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11 votes
1 answer
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DFT optical calculation and plotting for real and imaginary permittivity in VASP?

I have calculated Frequency dependent optical permittivity of Au using (VASP) my INCAR tag includes LOPTICS=.TURE., my OUTCAR ...
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9 votes
1 answer
240 views

A good software for DFT optimization and nonlinear optical properties

I'm running a series of calculation for nonlinear chromophores. The general pipeline is geometry optimization (B3LYP/def2-TZVP) -> Frequencies -> Hyperpolarizability calculation (M06-2X (or CAM-...
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12 votes
1 answer
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Why linear response is absent in a non-centrosymmetric system with time reversal symmetry?

In this paper, it is mentioned that a non-centrosymmetric system with time-reversal symmetry doesn't have a linear response. It is actually a consequence of the Onsager reciprocal theorem. But I didn'...
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Calculating hyperpolarizability in NWChem

I'm trying to make a pipeline geometry optimization -> calculation of polarizability/hyperpolarizability. And NWChem seems pretty good for it, the only thing I can't understand its how to calculate ...
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11 votes
1 answer
132 views

How can we make a mechanically unstable cubic system, stable

I have to calculate the elastic constants of a Cubic system using a Density functional theory-based software. A cubic system will be mechanically stable if it satisfies the Born-stability condition (...
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14 votes
2 answers
740 views

How to start with the optical properties of 2D materials with the VASP code?

I hope you are doing well. I am new to VASP, and my project is "Optical properties of 2D materials on VASP" but I have no idea how to run a simple calculation with VASP. I will be very ...
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11 votes
1 answer
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Are there any other options beyond increasing the k-sampling and the number of unoccupied bands, to achieve better results?

I am trying to determine the optical properties of bulk Aluminium and related alloys using Quantum ESPRESSO. I am using both the epsilon.x and the simple.x modules to get wavelength-dependent ...
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5 votes
1 answer
458 views

How to implement scissor-correction in VASP to study optical properties?

It is mentioned here that It is possible to correct for the DFT band gap error by introducing an empirical scissors correction, which is effectively a rigid shift of the conduction band with respect ...
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