6533b826fe1ef96bd1284627

RESEARCH PRODUCT

Stark effect in some lines of neutral bromine

subject

description

Abstract This work presents experimental results of profile parameters for prominent lines of neutral bromine, for which serious discrepancies between experimental values of different authors as well as between experimental and calculated values were observed. The observed discrepancies between shock tube and earlier arc experiments are very large. Our results of profile parameters, obtained also in a wall-stabilized arc, show acceptable agreement with the earlier arc measurements. It is obvious, that the shock tube experimental result is out of the range of acceptable inaccuracy and should be remeasured. The theoretical calculations based on different assumptions give also strongly divergent results. The doubtful results of calculations for intercombination lines (e.q. 4472 A ) could be expected, but the observed factor 2 or higher discrepancy for the other lines shows the need to find better theoretical approaches for profile parameter calculations. For generating the bromine spectrum a mixture of argon and bromine vapors was introduced in the central part of a wall-stabilized arc. The arc was operated at currents of the range of 25– 60 A . The amount of bromine vapors was changed by adjusting the thermostat temperature. The spectra were recorded using a grating spectrograph (PGS2), an optical multi-channel analyzer OMA4 and a IBM-PC type computer. The plasma diagnostics was based on measured emission coefficients of neutral argon and bromine lines and the measured half-width of the Ar I 4300 A line (LTE was assumed). Profiles of diverse types were fitted to data sets of experimental points. Griem profiles agreed normally better with the experimental results than Lorentz or Voigt profiles.