# Tag Info

13

There are several DFT based commercial or open source softwares that could be used to simulate the optical properties of nanomaterials, particularly metallic nanoparticles. Basically, what you are looking for is calculating the susceptibility tensor from Kubo-Greenwood relation: \chi_{ij}(\omega) = \frac{e^{2}}{\hbar m_{e}^{2} V} \sum_{n,m,\mathbf{k}} \...

10

Well, to answer properly this question first we would need a clarification about the nature of the CIF file. This type of file is Crystallographic Information File, which means that it is devoted to periodic, crystalline, and symmetric materials. In my opinion a core-shell nanostructure (CNS) is not fullfilling this requirements. In particular, the symmetry ...

8

Two things are mixed in the question. How to create atomistic model of a core-shell nanoparticle? Are both the core and the shell assumed to be crystalline? Most likely you will need is to write a small program that generates the required configuration by calculating atomic positions. You can create the first approximation of a (uniform) nanoparticle by ...

8

DDSCAT You can use the DDSCAT (Discrete Dipole Scattering) package for nanoparticles >5 nm. Many of the optical properties of nanoparticles (absorption, scattering, extinction coefficient) can be solved via classic electrodynamics, i.e. solving the Maxwell Equations when light interacts with a nano-sized object with no quantum packages necessary. To ...

8

Yes - you can just pre-calculate them and hard-code them into your code, so that the script is simply a conditional switch that returns the required array when given the atomic number, without any actual calculation. Although this gives a script that is much longer than it needs to be, it's less susceptible to unexpected errors, since the shell occupation ...

5

So I have been researching Quantum Dots but I will give you some advice on how could you go about creating your structure using VESTA and add ligands using IQ mol. You should watch this video first - https://www.youtube.com/watch?v=KxO5uLsvkRE.\ Moreover at the point where the instructor changes the central atom and uses that to create the bonds what you ...

4

1) Using CALYPSO with Quantum ESPRESSO I want to create a nanoparticle of CuO and predict it's structure. I've done unit cell relaxation with Quantum ESPRESSO. One tool to predict nanocluster structure is Calypso which is PSO-based. I'm using Quantum ESPRESSO with it. If anyone does Calypso structure prediction, what are some ways for predicting nanocluster ...

3

Did you check that the bulk structures are stable? If they are, then the Coulomb part should be working, and the problem might be in your model. This type of problem is actually relatively common. If you use potentials that have been fit for bulk materials i.e. perfect crystals, you're only studying a small range of the possible configuration space: the ...

2

From the standpoint of simulations, a quantum dot would be more like a smallish 3D system. Depending on the number of atoms in the qdot, it could be simulated directly. You would simply need set up an isolated arrangement of atoms. Some DFT programs allow you to turn off periodic boundary conditions (PBC), otherwise, you might simply leave the PBC on, but ...

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