Fr.: bande de Werner
A sequence of → permitted transitions in the → ultraviolet from an → excited state (C) of the → molecular hydrogen (H2) to the electronic → ground state, with ΔE > 12.3 eV and λ ranging from 1160 Å to 1250 Å. When a hydrogen molecule absorbs such a photon, it undergoes a transition from the ground electronic state to the excited state (C). The following rapid → decay creates an → absorption band in that wavelength range. See also → Lyman band; → Lyman-Werner photon.
Named after the Danish physicist Sven Theodor Werner (1898-1984), who discovered the band (S. Werner, 1926, Proc. R. Soc. London Ser. A, 113, 107); → band.