Spectroscopic analysis of independent discharges in molecular gases

Abstract

The schematic of the feed system and the structure of the discharge device is described in detail in [5]. The geometric dimensions of the discharge region are 2.7  4  40 cm. Preliminary ionization is achieved with the radiation of spark discharges positioned beyond a grid anode. The voltage on the capacitor can vary over the range of 12-35 kV. The discharge device allows one to obtain a volumetric discharge in COs, N2, He, and in their mixtures for the pressures of (0.i-i)'i0 s Pa. The spectra are recorded with an ST~-I spectrograph. It is necessary to have 25-100 pulses for normal darkening of the RF-3 photographic film (depending on the conditions of the experiment). The behavior of the intensity of individual molecular bands and spectral lines over time is observed with an MDR-2 monochromator, F~U-39 (or FEU-79) photomultiplier, and a dual-beam $8-2 oscillograph. Simultaneous recording of the signal with the F~U and the voltage pulse in the discharge enables one to determine the time at which the discharge pulse is formed in the spectrum of one or another line. The dimensions of the discharge region in the direction of the optical axes of the monochromator and the objective of the spectrograph are equal to 4 and 40 cm, respectively. A miniature image of the discharge region is projected onto an input slit in the spectrograph perpendicular to the plane of the electrodes. This method of measurement allows one to obtain intensity distributions for the recorded spectral lines in the direction of the anode-cathode [4] and, when the image is rotated by 90 ~ , in the direction perpendicular to the direction of the voltage of the electric field. In order to eliminate the illumination of regions pertaining to the cross section of the discharge region under investigation, a system of slotted diaphragms is used. An additional mirror is used for taking into account the optical depth of the plasma for vibrational transitions when conducting relative measurements of the excited states of the molecules. A qualitative analysis of the spectrograms for discharges in pure gases of C02, N2,