Questions tagged [python]

For questions about materials modeling scripts written in the Python programming language. Questions should focus on interfacing with existing packages and aspects related to modeling, not general debugging.

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34
votes
13answers
2k views

What is a good programming language for matter modeling?

What is a good programming language for matter (e.g. molecular or materials) modeling? Since this is a broad field, I don't expect there to be only one answer.
29
votes
2answers
678 views

How is Julia used in matter modeling?

What are the main uses and applications of Julia in matter modeling? Python for example is used in many codes, not to mention workflow automation and data processing. Are there any available codes or ...
27
votes
4answers
4k views

How to write my own density functional theory (DFT) code in Python?

I am a DFT user and at some point in the future, I would like to write my own DFT code in Python to help gain a deeper understanding of DFT. As mentioned in a previous answer people have written their ...
26
votes
3answers
2k views

How to "get my feet wet" in Density Functional Theory by simulating a water molecule using Python

I just saw I am a beginner in Density Functional Theory. What are some resources that could help me to learn the basics? and it reminded me that few years ago I'd asked How can I calculate the charge ...
19
votes
3answers
1k views

How to find Young's Modulus using stress strain curve using Python?

I am trying to find the The Young's Modulus of an aluminum alloy The yield stress Below is the data for the stress-strain curve. I tried finding the region where the slope is constant and to my ...
19
votes
0answers
263 views

What are the tools available for point defects calculations?

As far as I know, there are mainly PyCDT, PyDEF, pylada and some part of pymatgen. As a new user to those tools, which one would be a good choice? It would be appreciated if you could explain one of ...
16
votes
2answers
864 views

Open Source PyMol Conda Package: UnsatisfiableError

I'm having an issue installing the open-source version of Pymol using Anaconda on Windows. I have Python 3.8.3 installed and when I try to add the package with Conda using ...
16
votes
1answer
223 views

How to calculate t-zero temperature using Thermo-Calc- Python (TCPython) for multiple alloys?

T-zero temperature is the temperature at which the Gibbs energies of two phases are equal. Here, I wish to find the temperature at which FCC and BCC have same Gibbs energy. Thermo-Calc console mode ...
13
votes
3answers
1k views

Python script for convergence test

I want to do a convergence test of Ni using a Python script in Pyiron. Can someone please suggest how to write a script to test energy and k-mesh convergence?
13
votes
4answers
316 views

Is python sufficient for serious tensor network or DMRG calculations?

There are enough tensor-network/DMRG packages that support python (ALPS, OpenMPS, pyUni10) that it would seem (to an outsider) that it's possible to do some substantial work with DMRG without messing ...
13
votes
3answers
456 views

How to generate the high symmetry paths for band structure calculations?

Suppose I want to calculate the band structure of a material system along a specific high symmetry path in the Brillouin Zone. If the point group of the system is given, how can I easily compute the ...
13
votes
1answer
142 views

Generating numpy-compatible electron density from Molden / QC calculation

I'd like to use a variety of Python tools (e.g., matplotlib and Mayavi) to analyze orbitals plot electron density contours, etc. ...
12
votes
3answers
495 views

How to create a 3D band structure from DFT band structure calculation?

How can I create such a 3D plot using matplotlib? Like the one in Figure (a) below: I want to create it using DFT bandstructure calculation result
12
votes
1answer
99 views

Metropolis algorithm reduces energy in molecular simulation, but does not decrease euclidean distance

I am using an open source python package openmmtools to run a simple molecular simulation problem using the metropolis algorithm. I first load a default system of particles (alanine-dipeptide in ...
12
votes
1answer
143 views

What is the best program to manipulate numerical DFT wavefunctions to calculate custom matrix elements?

For pedagogical reasons, I am looking for ways to calculate quantum-mechanical quantities such as $\langle m | \dot{m}\rangle, \langle m | \dot{n}\rangle, \langle m | \ddot{n}\rangle$ using ...
12
votes
1answer
123 views

How to numerically solve real-space 1D time-independent Schrodinger equation using 2D momentum-space Hamiltonian?

Consider the usual simple 2-level graphene Hamiltonian with mass in momentum-space where: $$ H(k,V)=-t \sum_{\delta} [\cos(k\cdot\delta)\sigma_x-\sin(k\cdot\delta)\sigma_y+V\sigma_z], $$ where $t$ is ...
12
votes
1answer
372 views

Is there a more efficient hard sphere packing algorithm?

I am trying to pack hard-spheres in a unit cubical box, such that these spheres cannot overlap on each other. This is being done in Python. I am given some packing fraction ...
11
votes
4answers
2k views

How to make a python code that can read a .xyz file and find the distance between atoms?

I want to make a python script that will load an xyz file. From the xyz parameters, I need to find the distance between atoms, angle and dihedral between atoms. The file xyz have this structure: ...
11
votes
1answer
153 views

How to use wavefunctions/density to determine which orbitals lead to edge states?

I have a large matrix for a 1D zigzag edge model of an otherwise $3\times 3$ tight-binding Hamiltonian (3 basis functions, each corresponding to an atomic orbital), involving the variable $k_x$. The ...
11
votes
1answer
80 views

Interpret 2D and 3D data from a PubChem summary of organometallic molecule? Can I "flatten" it when showing on a surface?

I need to "build" an organometallic molecule in Blender/Python then represent it resting on a crystal surface. I'm looking at a PubChem summary for Chloroaluminum phthalocyanine and I can ...
11
votes
1answer
126 views

How to get order constitution data for single equilibrium calculation in Thermo-Calc's TC Python module?

I know that it is possible to get order constitution data for phases when using Thermo-Calc's GUI (e.g. to get "BCC_B2 DISORD" instead of just "BCC_B2") for a single equilibrium ...
11
votes
0answers
90 views

What are good protocols for creating a database based on python?

I am aware of software tools such as atomate, but that is quite specific to crystals. There are other equally specific workflows - I think we all have our own... What I am interested in is making my ...
10
votes
2answers
707 views

RDkit: While converting a *.sdf file to fingerprint, I'm facing several errors

suppl = Chem.SDMolSupplier('1.sdf') for mol in suppl: if mol is None: continue # print(mol.GetNumAtoms()) fps = [Chem.RDKFingerprint(x) for x in supply] I am ...
10
votes
2answers
139 views

Programs/Libraries for calculating solvent excluded surface and excluded volume

Given the 3D structure of a molecule (e.g. as *.mol) and a probe radius r, I want to calculate the solvent excluded surface (SES)...
10
votes
1answer
205 views

What is the right way to calculate <A><A>?

We asked a similar question somewhere else and someone advised trying here instead. How should we calculate $\langle A\rangle \langle A\rangle$ from data on dipole moments? It is a term in an ...
10
votes
1answer
266 views

How should I generate a radial distribution function (RDF) for an MD trajectory with python?

I am attempting to analyse the radial distribution function (oxygen to oxygen) for a ~400ps simulation on a droplet of water (MD done with NAMD). I am using the python library MDAnalysis to do this. ...
10
votes
1answer
65 views

Pycalphad most efficient way to gather equilibirum phase data for set of alloy compositions?

What's the most efficient way to get the equilibrium phases and phase fractions for a set of alloy compositions? For context, I'm coming from Thermo-Calc/TC-Python where I would just loop through the ...
10
votes
1answer
229 views

Generating SOAP descriptors in python

What is the best python package to construct Smooth Overlap of Atomic Positions (SOAP) descriptors given SMILES representation of a molecule? Is this even possible without providing 3D geometry? An ...
10
votes
1answer
120 views

Computing optimized 3D structures in python that take solvent into account

I have been using RDKit to generate 3D coordinates, cleaning-up the structures using a general-purpose force field as follows: ...
9
votes
4answers
905 views

How to make a python code that can read a .xyz file and find distance, angle and dihedral angle between atoms?

I want to make a python script that will load an xyz file. From the xyz parameters, I need to find the distance between atoms, angle and dihedral between atoms. If I have a xyz coordinate in this ...
9
votes
3answers
805 views

Molecular visualization software in Jupyter (IPython) Notebooks

Jupyter notebooks have always been a great way for me to create high-quality graphs, and write code. The features also continue to improve with packages such as Jupyter Lab, and now Jupyter Books, ...
9
votes
2answers
591 views

Python program that returns elements from a SMILE string

Given a SMILES string for a molecule, I want to know the elements in the molecule, I then send this to basis_set_exchange to get a "custom" basis set for use in Gaussian. This seems like ...
9
votes
1answer
101 views

Normalization condition in evaluating the radial distribution function for a hard-spheres system

I am trying to simulate a 3D hard-spheres in a box system in Python. The idea behind this is that I have to create a system in a 1x1x1 box with periodic boundary conditions and with $N = 500$ ...
9
votes
2answers
68 views

Evaluating the MSD of my simulation

I am running a molecular dynamics simulation of water in TIP3P, and I am storing the positions of my particles in a 2D array called relevant_positions. The number ...
9
votes
1answer
302 views

Using OpenBabel or RDKIT Python API to generate conformers from a SMILES string

I have a bunch of monomers in the form of SMILES string and I want to generate conformers from them. At the moment, I am using RDKit to convert these SMILES strings to .sdf files, then using ...
9
votes
0answers
46 views

Is there a script that will suggest (hkl) indices based on distances in an electron diffraction pattern for a known crystal structure?

I am looking for a script (preferably in Python) that will suggest (hkl) indices based on distances in an electron diffraction pattern. The crystal structure is known,i.e. I have the CIF file and know ...
9
votes
0answers
287 views

I wrote a Python code to do MD for a Lennard-Jones fluid but the VACF is wrong: What might be the problem? [closed]

I am trying to write a molecular dynamics simulation for a Lennard-Jones fluid in a box with periodic boundary conditions. The box has no net momentum. I am writing this in python. I have written a ...
8
votes
1answer
176 views

Functional group detection for group contribution methods

I would like to be able to parse a molecule into its functional groups, and, also, know the number of occurrences of each. A similar question was asked on matter modelling specifically for xyz files. ...
8
votes
1answer
113 views

What are open source options to simulate kinematical electron diffraction patterns?

I tried using the python package diffsims. I get an image, but not a diffraction pattern I was expecting. ...
8
votes
0answers
59 views

Bloch wave function extraction for the specific k-points and specific band from QE calculation [closed]

I would like to use QE to obtain u_K(r), which is the Bloch wave function of spin-up maximum valance band at K point. If I define the K point in the input file and do an SCF calculation by QE ...
7
votes
2answers
125 views

RDkit and PySmiles results differ on some SMILES strings

I recently started using both pysmiles and RDkit to parse SMILES strings into molecules. ...
7
votes
1answer
143 views

How to build the [111] slab model of NiSe2 with different terminations with ASE tool?

The following figure is the bulk structure of NiSe$_2$ downloaded from the materials project database. Now I want to study the properties of its [111] plane. In detial, I cut the slab with atomic ...
7
votes
1answer
83 views

Help with Definitions in Numerical Calculation of Multiband Berry Phase

In the third chapter of Vanderbilt's book, they discuss the so-called multiband parallel transport and provide a scheme for numerical calculations that is similar to the single band case (where the ...
7
votes
1answer
208 views

How to understand the wavefunction outputed by QE with HDF5 format?

Following the answer to my question: What is the best program to manipulate numerical DFT wavefunctions to calculate custom matrix elements?, I compiled Quantum ESPRESSO with the hdf5 flag on, and now ...
7
votes
1answer
45 views

Thermo-Calc: how to suspend specific composition sets?

I am attempting to calculate the driving force of nucleation for several different precipitate phases using TC-Python. To this I want to suspend all phases, except for the matrix phase (e.g. FCC_L12). ...
7
votes
1answer
54 views

Fractal dimension (SEM image) using the box-counting method

I am trying to discover the fractal dimension of the image of the following dendrite that was obtained by SEM (scanning electron microscope) by the box-counting method (Python). I found this code on ...
7
votes
0answers
49 views

Convert standard image file format to py4DSTEM datacube?

I want to analyze a diffraction pattern. Py4dSTEM is asking for a datacube to start with. I thought it might be able to convert an image to this format: ...
6
votes
1answer
140 views

Pycalphad "Failed while parsing" Yttrium from light alloys database

The code in question is just 2 lines used to import the "COST507 database for light alloys" (downloaded from the opencalphad homepage http://www.opencalphad.com/). ...
6
votes
1answer
81 views

How is the atom selection going wrong when creating the collective variable?

I'm trying to create a CV for angle theta. To make this calculation, the right atom selections need to be made. The function is given below: ...
6
votes
1answer
66 views

Downloading ASE (Atomic Simulation Environment) on older versions of Python

I'm trying to install something called ASE that models atomic structures. I have ASE currently installed on python 3.7, however I need to run scripts that can import and recognize ASE in an older ...