Spectra are frequency emissions or radiations or signature of some vibration source such as an element (atomic spectra). Spectra data is usually given in wavelengths. see Hyperfine Structure

Carbon Spectra
(courtesy LaserStars.org)



Source Materials
Spectra of Gas Discharges
NIST Atomic Spectra Database - Line Data
NIST Atomic Spectra Database - Energy Data
Handbook of Basic Atomic Spectroscopic Data - download page
See Also
Aliquot
Chord
Chord of Mass
Chord of the Mass
Crab Nebular Spectral Views
Figure 8.14 - Some Basic Waveforms and their constituent Aliquot Parts
Hyperfine Structure
Light
molecular aggregation
Order
Signature
spectral component
Spectrum
Subdivision
Vibration Signature