Unanswered Questions
59 questions with no upvoted or accepted answers
22
votes
0
answers
248
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 ...
- 15.9k
11
votes
0
answers
145
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
109
views
Is the formula of a Dyson orbital independent of whether there is degeneracy or not in the HOMO of the neutral?
A Dyson orbital is defined as:
$$
\textrm{Dy}(x) = \int dx_1 \ldots dx_{N-1} \, (\Psi^+(x_1,\ldots,x_{N-1}))^* \, \Psi^0(x_1,\ldots,x_{N-1}, x),\tag{1}
$$
where $\Psi^0$ and $\Psi^+$ are the total ...
8
votes
0
answers
96
views
How do I identify an oblique surface mesh?
I have drawn three surface meshes from a hexagonal material for the $(0001)$, $(1\bar{1}00)$ and $(1\bar{1}01)$.
The first one would be the top horizontal surface of the hexagonal structure, the ...
- 15.9k
7
votes
0
answers
57
views
Database (or table) of functions obeying symmetry properties of space groups
I'm looking for a table or database containing mathematical functions that belong to crystallographic space groups by having the same symmetry elements.
Imagine a 2D square planar lattice. It has a 4-...
7
votes
0
answers
448
views
Straightforward formalism to get sets of lattice vectors of fcc (111), (110) and (100) facet surfaces that I can also cite?
I am simulating low energy electron diffraction (LEED) from a polyfaceted sample. Usually it's a single, well-defined flat crystalline surface.
Since low energy electrons (below a few hundred eV) only ...
- 2,074
7
votes
0
answers
201
views
How to convert lab frame quaternions and plane normal to misorientation quaternion and crystal plane normal for grain boundaries?
Background
Let qA and qB represent unit, orientation quaternions of grain A and grain B of a grain boundary in the lab reference ...
- 15.9k
5
votes
0
answers
41
views
Rich editing of ASE images
I want to produce some images related to graphene-like materials.
I was able to draw them using ASE visualize module after constructing the atomistic model. However ...
- 24.2k
5
votes
0
answers
396
views
How can I properly plot this .cube file in Python?
Motivation for Post: I saw a question about how to plot a .cube file recently on the Mathematica & Wolfram Language Stack Exchange. It was marked "off-...
- 143
5
votes
0
answers
47
views
How to transform a perturbed surface structure to a reference surface structure?
Say I have a bulk FCC Pt structure obtained from Materials Project with a lattice constant a = 3.94 Å. I first did DFT to relax the bulk structure, and the optimized lattice constant becomes for ...
- 1,970
5
votes
0
answers
162
views
Actual calculation of Coulomb energy in DFT softwares
I have a question about the actual calculation of classical Coulomb interaction term in density functional theory (DFT) softwares.
Of course I understand the form Coulomb energy as:
$\int\int \frac{\...
- 1,799
5
votes
0
answers
120
views
How to find the most stable facet for a crystal?
I am trying to find the most stable facet for a crystal, but since there are many possible choices, like (1 0 0),(1 1 0),(1 1 1),(2 1 0), etc. My questions is:
I am wondering how should I determine ...
4
votes
0
answers
44
views
What software is fit for calculating an atomic and electronic structure of a newly formed nanocluster after injecting impurities into an initial one?
Let's suppose there is a nanocluster and its structrure is known. The problem is to inject impurities into this nanocluster. The impurities can be injected in different quantitites but consist only of ...
- 1,027
4
votes
0
answers
37
views
Calculating degrees of freedom with fixed symmetry
I stumbled upon a problem recently: I want to compute the number of degrees of freedom for a crystal/molecule if its symmetry is fixed.
I think what needs to be done is to compute the number of normal ...
- 1,467
4
votes
1
answer
141
views
How to use rigid scan with dummy atoms in gaussian?
I am trying to use rigid scan using gaussian 09. In my case, there are three water molecules and I have placed a dummy atom at the centroid of the three water molecules. For simplicity, I want to ...
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