A STUDY OF THE EMISSION INTENSITIES OF Cr LINES FROM SHOCKED GASES CONTAINING Cr(CO)6

Abstract

Argon–nitrogen mixtures (9/1) were inoculated with traces of Cr(CO)6 (0.026%) and shocked to temperatures in the range 3500 °K to 5700 °K. The intensities of a violet line (7P2 → 7S3) and a triplet of green lines (5P3,2,1 → 5S2) were measured concurrently, with a dual-channel spectrograph. Exclusive of runs for which T > 5000 °K, the variation of intensity with temperature was brought to agreement with theoretical predictions under the assumption that the N2 vibrations, the dissociation of Cr(CO)6, and the ionization of Cr attained their equilibrium states, but allowance had to be made for self-absorption. The dependence of the rise times on temperature suggest that the excitation and ionization of Cr is predominantly due to collisions with electrons. The over-all shapes of the recorded light pulses were qualitatively accounted for. It is suggested that extraneous background radiation contributed to the measured intensities for samples shocked to temperatures above 5000 °K.