The phrase "spectral lines" refers to specific colors or wavelengths of light that are released or absorbed by atoms or molecules. These lines help scientists identify and study different elements or substances. Full definition
Gamache, R.R., R. Lynch, and S.P. Neshyba, 1998: New developments in the theory of pressure - broadening and pressure - shifting of spectral lines of H2O: The complex Robert - Bonamy formalism. (pubs.giss.nasa.gov)
Ma, Q., R.H. Tipping, G. Birnbaum, and C. Boulet, 1998: Sum rules and the symmetry of the memory function in spectral line shape theories. (pubs.giss.nasa.gov)
Such a break is found in the spectrum of all remote objects (from the crowding of absorption lines creating an effect known as the «Lyman - alpha forest» before the Lyman - alpha spectral line at rest wavelength 121.6 nm). (members.nova.org)