Atomic data from plasma based measurements and compilations of transition probabilities

Summary from only given. High efficiency electrical light sources used in lighting applications are based on electrical discharges in plasmas. The systematic search for improved lighting plasmas increasingly relies on plasma discharge modeling with computers and requires better and more comprehensive knowledge of basic atomic data such as radiative transition probabilities and collision cross sections. NIST has ongoing research programs aimed at the study of thermal equilibrium plasmas such as high pressure electric arcs and non-equilibrium plasmas in radio-frequency discharges and high current hollow cathode lamps. In emission experiments we have measured branching fractions and determined absolute transition probabilities for spectral lines in Ne I, Ne II, F I, O I and O II. In case of the Ne measurements the line radiation emitted by a high current hollow cathode lamp was analyzed with a 2 m monochromator. In addition, the spectra of Ne I and Ne II were measured with a UV Fourier transform spectrometer at very high spectral resolution. The line intensities were subsequently calibrated to absolute radiances. Where complete sets of transitions from an upper level could be observed, recent lifetime data for these levels were used to determine absolute transition probabilities. The accuracy of our branching fraction data is 5% for the stronger lines.