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'''Generating input file for formation energy''' | '''Generating input file for formation energy''' |
Revision as of 15:49, 13 January 2022
Contents
Software and resources
Structure and crystallography
ICSD database
Automatic login through EZproxy (www.ub.uio.no/english/using/remote-access.html).
Materials project
Contains structures optimized by DFT that can be downloaded in several formats including .cif or POSCAR. Choose 'Conventional Standard' CIF.
Login with a Google account (available with UiO username www.uio.no/english/services/it/store-collaborate/gsuite/).
International Tables for Crystallography
Complete overview of space-group symmetry and more.
Shannon Ionic Radii
Reference [1]
Binding energies of molecules
Todo: Table of binding energies with reference (e.g., NIST)
Catalysis
Catalysis Hub
Database of reaction energies and barriers from DFT calculations.
Visualization
VESTA
jp-minerals.org/vesta/en/ (Windows, macOS, Linux)
View periodic structures, charge densities and more.
Recommended settings for improved figures
Objects > Properties > Atoms/Bonds/Polyhedra Specular: 40 40 40 Shininess (%): 1 View > Overall Appearance... Ambient: 10 Diffuse: 70
Avogadro
avogadro.cc (Windows, macOS, Linux)
View and edit molecular structures and optimize molecular geometry through molecular mechanics.
Diamond
www.crystalimpact.com/diamond/ (Windows: Licence)
View and edit periodic and molecular structures.
VMD
www.ks.uiuc.edu/Research/vmd/ (Windows, macOS, Linux)
View and animate structures from molecular dynamics simulations.
P4vasp
github.com/orest-d/p4vasp (macOS, Linux)
Visualizing periodic structures, density of states and band structures.
Packages
Spyder
www.spyder-ide.org (Windows, macOS, Linux)
Scientific python developer environment.
Atomic Simulation Environment (ASE)
wiki.fysik.dtu.dk/ase/ (Module available on Saga)
Set of tools and Python modules for setting up, manipulating, running, visualizing and analyzing atomistic simulations.
Example of a script for generating an (1 1 1) surface slab of palladium
#!/opt/local/bin/python from ase.io import read from ase.io import write from ase.build import fcc111 from ase.build import fcc100 from ase.build import fcc111_root
slab = fcc111_root('Pd', 3, size=(1,2,7), a=3.9438731474981594, vacuum=5.0)
write('Pd-111-gb.cif', slab, 'cif')
VASPKIT
vaspkit.com (macOS, Linux)
Generate input files and data processing.
CatMAP
CatMap is a catalyst Micro-kinetic Analysis Package for automated creation of micro-kinetic models used for studying kinetics and screening new catalysts.
https://catmap.readthedocs.io/en/latest/index.html
CatMap can be installed directly via pip:
pip install --upgrade https://github.com/SUNCAT-Center/catmap/zipball/master
To use the package add this directory to the PYTHONPATH, e.g. in bash shell:
export PYTHONPATH=$HOME/THIS_FOLDER_PATH:$PYTHONPATH
Input File Structure
The TableParser accepts inputs in a tab-separated text file. An example of the header and first few lines are provided below:
The following column titles are required for a functional input file:
- surface_name
- site_name
- species_name
- formation_energy
- frequencies
- reference
Generating input file for formation energy
You can use the python script under /CATMAP/catmap/tutorials/1-generating_input_file/generate_input.py
Creating a Microkinetic Model
Check the example of CO oxidation in the path of /CATMAP/catmap/tutorials/2-creating_microkinetic_model
One of the most important aspects of the “setup file” is the “rxn_expressions” variable which defines the elementary steps in the model. For this simplified CO oxidation model we will specify these as:
rxn_expressions = [ '*_s + CO_g -> CO*', '2*_s + O2_g <-> O-O* + *_s -> 2O*', 'CO* + O* <-> O-CO* + * -> CO2_g + 2*', ]
The first expression includes CO adsorption without any activation barrier. The second includes an activated dissociative chemisorption of the oxygen molecule, and the final is an activated associative desorption of CO2. More complex models for CO oxidation could be imagined, but these elementary steps capture the key features. Note that we have only included “*
” and “*_s
” sites since this is a single-site model for CO oxidation. This means that all intermediates will be adsorbed at a site designated as “s
”. These reaction expressions will be parsed automatically in order to define the adsorbates, transition-states, gasses, and surface sites in the model.
Phonopy and Phono3py
Phonopy is an open source package for phonon calculations at harmonic and quasi-harmonic levels. Phono3py is another open source package for phonon-phonon interaction and lattice thermal conductivity calculations.
TDEP
Extract force constants, phonon dispersion relations, thermal conductivity, and generate special quasirandom structures (SQS)
Available on Saga (/cluster/shared/tdep/bin). Use the following modules
module purge module load Anaconda3/2019.03 module load intel/2018b module load imkl/2018.3.222-iimpi-2018b module load HDF5/1.10.2-intel-2018b
Generate SQS supercell from from a unit cell POSCAR file named 'infile.ucposcar'
Example of 'infile.ucposcar' for a A-site doped SrTiO3 unit cell where the disordered site is designated 'ALLOY' (2 elements: 52% Sr and 48% Ca)
Sr1 Ti1 O3 1.0 3.945130 0.000000 0.000000 0.000000 3.945130 0.000000 0.000000 0.000000 3.945130 ALLOY Ti O 1 1 3 direct 0.000000 0.000000 0.000000 2 Sr 0.52 Ca 0.48 0.500000 0.500000 0.500000 0.500000 0.000000 0.500000 0.500000 0.500000 0.000000 0.000000 0.500000 0.500000
Generate 2x2x2 SQS supercells (five supercells will be generated outfile.sqs_001-005)
generate_structure -d 2 2 2
Spinney
Python package dedicated to the study of point defects in solids. Can be used to calculate the correction energy due to electrostatic finite-size-effects in charged supercells, defect formation energies and transition levels, and defects concentrations.
References
- ↑ R.D. Shannon, Revised Effective Ionic Radii and Systematic Studies of Interatomic Distances in Halides and Chalcogenides, Acta Cryst. 1976 (A32) 751-767