EXCITATION IN SOURCES FOR SPECTROSCOPIC ANALYSIS

Abstract

From the viewpoint of the spectroscopic analyst, it is desirable to obtain some knowledge concerning the phenomena that result in the emission of radiation from certain types of sources. Results of intensity measurements on the vibration bands of the violet cyanogen system, and on certain lines in the tin spectrum, indicate that in the condensed d-c. and a-c. spark discharges the excitation is predominantly thermal in character, just as in the freely burning carbon arc. The values for the maximum temperature in the discharge columns of these three sources were found to be very nearly 9500°, 7800°, and 7000° K., respectively. It was observed, however, that the Boltzmann character of the distribution over various energy states was lost when the usual inductance was removed from the d-c. spark circuit.One of the five investigated tin levels exhibited an abnormal behavior, which may possibly be accounted for by the occurrence of collisions of the second kind. There is also evidence to show that the emitting column is surrounded by a relatively cold layer of atoms originating in the material placed on the electrode. This layer absorbs some of the intensity of the lines ending on the ground level.