Accession Number : AD0262100

Title :   THE USE OF THE SHOCK TUBE AS A SPECTROSCOPIC SOURCE WITH AN APPLICATION TO THE MEASUREMENT OF GF-VALUES FOR LINES OF NEUTRAL AND SINGLY IONIZED CHROMIUM

Corporate Author : MICHIGAN UNIV ANN ARBOR

Personal Author(s) : WILKERSON,T. ; LAPORTE,O.

Report Date : JUN 1961

Pagination or Media Count : 1

Abstract : With chromium carbonyl as the additive, the gas behind the reflected shock emitted intense lines of neutral and singly ionized chromium (CrI and CrII). Line intensities were measured by heterochromatic photometry, using the anode crater of a carbon arc as the primary radiation standard. The state of the gas was computed from shock tube theory, taking account of dissociation, ionization, and excitation. Computed atomic populations were used, in conjunction with the theory of radiative transfer, to derive absolute gf-values of the lines from their observed intensities. The measurements covered twenty lines of CrI and eight lines of CrII in the wavelength region 4500-5000 A. The relative magnitudes of the CrI gf-values were quite different from the relative values previously found in a furnace experiment. The new values rectify the anomalies attributed to CrI in arcs and the sun on the basis of the previous work. The results of other experiments are compared to a few of the new absolute gfvalues of CrI. The new values are three to five times greater. The gf-values for CrII are apparently the first to be measured for this ion. Observations were made of the ionization relaxation of CrI immediately behind the reflected shock. (Author)

Descriptors :   *ATOMIC SPECTROSCOPY, *CHROMIUM, *MOLECULAR SPECTROSCOPY, *SHOCK WAVES, GASES, HIGH TEMPERATURE, IONS, SHOCK TUBES

Distribution Statement : APPROVED FOR PUBLIC RELEASE