  The deviation of the electron density around the nuclei from spherical
symmetry determines the electric field gradient (EFG), which can be measured by
various types of spectroscopy. Nuclear Quadrupole Resonance (NQR) is
particularly sensitive to the EFG. The EFGs, and by implication NQR
frequencies, vary dramatically across materials. Consequently, searching for
NQR spectral lines in previously uninvestigated materials represents a major
challenge. Calculated EFGs can significantly aid at the search inception. To
facilitate this task, we have applied high-throughput density functional theory
calculations to predict EFGs for 15187 materials in the JARVIS-DFT database.
This database, which will include EFG as a standard entry, is continuously
increasing. Given the large scope of the database, it is impractical to verify
each calculation. However, we assess accuracy by singling out cases for which
reliable experimental information is readily available and compare them to the
calculations. We further present a statistical analysis of the results. The
database and tools associated with our work are made publicly available by
JARVIS-DFT ( https://www.ctcms.nist.gov/~knc6/JVASP.html ) and NIST-JARVIS API
( http://jarvis.nist.gov ).
