THE SPECTRUM AND TERM SYSTEM OF C-IV

This paper reports an investigation of the spectrum and term system of Li-like carbon, C IV. Between 200 and 7750 Angstrom a total of 105 C IV lines have been identified by combining previously known data with new spectra recorded by the beam-foil technique and from observations at the JET tokamak. A comprehensive term system, with accurate energie s for all levels up to n = 12, is constructed from the identified tran sitions. Semiempirical series formulae are also given, allowing reliab le extrapolations to still higher n values. The ionization energy is d etermined to (520 175.3 +/- 1.5)cm(-1), which confirms recent theoreti cal predictions that include quantum electrodynamical (QED) correction s.