Spectra formed by bands consisting of rotational lines originating from rotational, vibrational and electronic transitions of molecules. These may be emission or absorption spectra.
PAC, 1985, 57, 1453
(Nomenclature, symbols, units and their usage in spectrochemical analysis - V: Radiation sources (Recommendations 1985))
on page 1461
IUPAC. Compendium of Chemical Terminology, 2nd ed. (the "Gold Book"). Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford (1997). XML on-line corrected version: http://goldbook.iupac.org (2006-) created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN 0-9678550-9-8. doi:10.1351/goldbook