Questions tagged [space-groups]
For questions about group theory and applications of symmetry groups of a configuration space.
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How to generate the remaining sites in a cubic lattice from a given POSCAR/cif in Python?
For example, I intend to generate the remaining sites of the Cr cubic lattice but the POSCAR file provides limited info on the number of atoms present as shown below. Is there a way to implement this ...
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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 showing the same symmetry elements.
Let me provide an example since it might at ...
- 141
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How do I know which is the asymmetric unit of a unit cell?
I need the number of independent atoms in the asymmetric unit
I have to introduce them in this form:
...
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Primitive Translation Vectors from Lattice Vectors (with varying Space Groups)
I am looking at some raw POSCAR data of some Primitive Cells, and I wonder how I can get a simplified directional representation of the lattice vectors. I have two examples:
Example 1:
...
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Reciprocal lattice and k-lattice belong to different groups in VASP
I am trying to do geometry optimization of TiO2 with VASP.
Here is the POSCAR file, which I get from the Materials Project.
...
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About LaCrO3 space group stability
I found two space groups of $\ce{LaCrO3}$ material Pnma and Pm-3m. If someone is familiar with this material, please help to understand which phase is more stable. what are the factors that determine ...
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How to determine the irreducible representation of an atomic orbital at a K point?
In this paper "Unified theory of direct or indirect band-gap nature of conventional semiconductors", the authors calculated the irreducible representations of atomic orbitals at three K ...
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Crystallography: How to sample *unique* structures from configuration space? (binary alloy supercell) [closed]
I'm working with a binary alloy system (call it 'AB'), and I'd like to generate a few unique configurations for DFT purposes.
My primitive cubic unit cell consists of 4 atoms; i.e. 4 positions. Thus, ...
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What are good tools for visualizing glide planes and screw axes?
While there are a few tools for visualizing crystal structures, I'm particularly curious to know tools for visualizing space group symmetry, including:
screw axes
glide planes
I teach a class on ...
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What's the information contained in a character table of a group? [closed]
This question has an answer on the Chemistry Stack Exchange: Understanding group theory easily and quickly.
Anyone wishing to add alternative or additional perspectives that aren't already covered in ...
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How to analyze the band symmetry with Quantum ESPRESSO?
This question is related to this paper: J. Phys. Chem. Lett. 2017, 8, 13, 2999–3007
The above figure shows symmetry analysis for the band structure. The author writes:
The band symmetry and parity ...
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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 ...
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answer
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What does it mean to assign group operations to distinct sets for space groups?
I am trying to understand space groups in crystallography. In International tables for crystallography, for a nonsymmorphic space group, they list some symmetry operations. 8 of them are listed under ...
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Why does mcsqs change the space group of generated SQS?
I made a binary special quasi-random structure (SQS) using mcsqs (distributed as part of the ...
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Are there computational methods for the determination of the point group symmetry of a molecule of a given geometry?
I am aware that there exists a flowchart about how to determine the point group of a molecule with a given geometry, such as given in the diagram available in
ChemLibre Texts. If we just look at the ...
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Inversion symmetry in 2D materials
Transition metal dichalcogenides (TMDs) are composed of three atomic planes and often two atomic species: a metal and two chalcogens. The honeycomb, hexagonal lattice has three fold symmetry and can ...
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Symmetry of glide planes [closed]
I am trying to understand the symmetry elements of space group number 194 (P$6_3$/mmc), which is hexagonal and has 24 symmetry operations.
In the table of symmetry operations it says that it has three ...
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How is group theory used to deduce which of these integrals are equal to 0?
The number of all two-electron integrals:
$$
\tag{1}
\langle \phi_1 \phi_2|\phi_3\phi_4 \rangle = \int d^3\mathbf r' \int d^3\mathbf r'' \, \phi_1(\mathbf r'') \, \phi_2(\mathbf r') \frac{1}{|\mathbf ...
- 595
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4
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How to analyze the space group of a relaxed structure that has fractional site occupancies
I am using VASP package to model a material that has fractional site occupancies. An appropriate supercell (cif) was generated using supercell package and converted ...
- 1,962
11
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2
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Is the original structure invalid if it's found later that the material crystallises with a slightly different space group symmetry?
I am studying a material which was first discovered in the early 1960s. It was reported then that it crystallized in the hexagonal $P6_3/mmc$ space group. Recently the material was synthesized again ...
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How can I create a .CIF file from x-ray diffraction data in a paper, for compound not found in crystallographic database
I tried to recover a .CIF file (Crystallographic Information File) with the crystal structure for the compound discussed in a paper by Reuter et. al.[1], strontium hydroxide octahydrate - $\ce{Sr(OH)2·...
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Enforce a space group on a given crystal structure
If I have a CIF that is P1, is there a (preferably free) code that can map the structure to some user-specified space group? I know that there are ways to do similar things with molecular systems. For ...
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How to do periodic DFT calculations using Quantum ESPRESSO?
I have only done quantum mechanical computations using non-periodic wavefunctions. I'd like to try to periodic-wavefunction density functional theory.
Quantum ESPRESSO seems like a good package ...
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