datasetphysics.nist.gov
physics.nist.gov
Access: open. Spectral lines/levels (frequencies/energies) for physics/engineering
datasetwebbook.nist.gov
webbook.nist.gov
Access: open. Thermochemical/spectral/reference data (energy transfer + materials)
datasetdata.nist.gov
data.nist.gov
Access: open. Broad science/engineering data