Unanswered Questions

355 questions with no upvoted or accepted answers
19 votes
0 answers
1k views

Interpreting electron localization function (ELF) results

Studying the interaction of a boron-nitride nanostructure with lead, we calculated the wave function using Gaussian software (single point energy with basis-set mix 6-311G++/lanl2dz and hseh1pbe ...
19 votes
0 answers
229 views

Is there a software that can do derivatives with respect to user defined vibrational modes?

I'm doing some property calculations that depend on a sum of derivatives of some quantity with respect to normal vibrational modes. I was hoping to find some physical intuition relating the type of ...
14 votes
0 answers
337 views

Calculating the Chern number on a 2D surface of a 3D insulator

I want to calculate the Chern number of a surface of 3D time reversal insulator. I know the 3D topological insulator is characterized by the Z2 index annd that the Chern number can be used to ...
12 votes
0 answers
243 views

Orbital magnetization in periodic solids

The orbital magnetization in periodic solids has been nicely described by the so-called modern theory of magnetization [1,2,3,4]. $$\tag{1} \mathcal{M}_{orb} = -\frac{1}{2} \Im \sum_{n,\mathbf{k}} f_{...
12 votes
0 answers
94 views

A viscoelastic material with nonconvex memory kernel?

The title is basically my question. Viscoelastic materials are characterized by a constitutive equation between stress and strain involving a convolution integral. This integral is weighted with a ...
11 votes
0 answers
264 views

Calculating Core-Level Binding Energies (XPS) using DFT

I'm pretty new to DFT calculations but I'm trying to learn how to do X-ray photoelectron spectroscopy (XPS) calculations, particularly for open-shell molecular systems in common non-periodic DFT codes....
11 votes
0 answers
138 views

Handling multiple self-consistent solutions with DFT+U

It is well-established that within the DFT+U framework, one can achieve several self-consistent solutions with greatly varying energies for the same exact magnetic ordering. In 2010, Meredig et al. ...
10 votes
0 answers
128 views

Is it possible to calculate non-resonant Raman coefficient in Quantum ESPRESSO for systems that require smearing to converge?

In Quantum ESPRESSO turning lraman to true in the ph.x input is not possible if the material is made to converge using smearing. Is there any way to circumvent this, as my material isn't a metallic a ...
10 votes
0 answers
229 views

How to plot the electrostatic potential calculated with XTB?

Following this question, I am interested now in plotting the electrostatic potential as calculated with the XTB program. I found how to set up the calculation but as a result, I got three files that I ...
9 votes
0 answers
118 views

Have FDTD methods made inroads into dynamical simulation of electron and/or X-ray scattering by crystals?

I'm afraid this question might be too basic or too naive or both, but here goes! For optical diffraction by periodic nano-structures (gratings, semiconductor manufacturing metrology) the rigorous ...
8 votes
0 answers
99 views

How to go from zero to hero in Machine Learning for materials modelling

I am interested in exploring the use of machine learning tools to accelerate molecular dynamics simulation probably by training machine learning potentials. While I have found some papers that apply ...
8 votes
0 answers
102 views

How does the line search in geometry optimisations work?

I am trying to write a Newton-Raphson geometry optimisation script in python (Current version of my code) using the energy, gradient and Hessian from Gaussian 16. In order to reach a minimum, I would ...
8 votes
0 answers
201 views

Different Results obtained while doing multiple runs from same inputs in VASP

I have been trying to optimize the parallelization parameters in VASP. By varying the parameters(such as KPAR and NCORE) I am trying to reduce the Elapsed time that is printed at the end of each line. ...
8 votes
0 answers
128 views

How to do parity analysis of band extrema?

To check whether electronic transitions are allowed between valence band maximum (VBM) and conduction band minimum (CBM) as per Laporte's rule, the parity of VBM/CBM is needed to be known. This paper ...
8 votes
0 answers
90 views

What are some recent significant developments/studies in theoretical nonlinear chemical dynamics?

During my undergraduate studies, I was introduced to oscillatory and nonlinear reactions, which are essentially chemical reactions oscillating far away from equilibrium conditions - A very visual ...

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