Fig 1.
Crystallographic data contained in the COD database in the CIF format is converted to DFT input by applying the Pymatgen package. DFT electronic structure calculations are performed using the VASP package. The DFT output (band structures and density of states) along with the basic crystallographic data from the CIF files are stored in the OMDB database, which also provides data mining tools to retrieve materials with specified by users electronic structure properties.
Fig 2.
Histogram of number of atoms per unit cell for 37,941 organic compounds from four experimental organic chemistry journals contained within the COD database.
Blue solid line denotes log-normal fit with a median value exp(μ) of 222.04 atoms and a standard deviation σ of 0.64 ln(atoms).
Table 1.
Summary of the input crystallographic data and rough estimation of the computational resources required to complete DFT calculations for the 37,941 organic compounds from four experimental organic chemistry journals contained within the COD database.
Core hours (c×h) are estimated based on the actual computational time of self-consistency calculations followed by density of states and band structure calculations on a single-core Intel Xeon 2.2 GHz assuming complexity of the DFT algorithm.
Fig 3.
Web interface of the OMDB database.
A web page with basic crystallographic information about a material, interactive band structure and density of states plots.
Fig 4.
Web interface of the advanced electronic band structure search.
Users can search for gap presence/absence of particular size in the energy range.
Fig 5.
Histogram of the band gap Δ (without distinction between direct and indirect gaps) for 6461 organic materials within the OMDB database.
Red solid line denotes Gaussian fit with a mean value μ of 2.98 eV and a standard deviation σ of 1.01 eV.