Number density of the 5s states during the ionisation relaxation of shock heated krypton
Abstract
The number density n sub d of the first excited level of krypton is determined during the ionization relaxation through the timeresolved absorption spectroscopy of the Kr I line 1s5  2p9 at a wavelength of 811.3 nm. Using a 1m grating monochromator and a pulsed continuous background, light source densities between 2 x 10 to the 15th/cu m and 2 x 10 to the 18th/cu m are measured. Simultaneously, the electron densities are measured with a 4mm microwave interferometer, and the values range from 2 x 10 to the 18th/cu m to 4 x 10 to the 19th/cu m. A diaphragm shock tube with a cross section of 52 x 52 sq mm and a length of 6 m is used to investigate shocks having Mach numbers ranging from M equals 12 (p sub 1 equals 4 torr) to M equals 8 (p sub 1 equals 40 torr). The shock tube is evacuated with a diffusion pump. Gassing introduces an impurity level ranging from 7 ppm (p sub 1 equals 40 torr) to 70 ppm (p sub 1 equals 4 torr), the test gas being Kr 4.0. The experimental results are compared with model calculations in order to deduce effective cross section constants. The reaction kinetics is modeled through a modified twostep ladderclimbing model under the assumption of a Maxwellian distribution function of the electrons.
 Publication:

Shock Tubes and Waves
 Pub Date:
 1982
 Bibcode:
 1982stw..proc..510Z
 Keywords:

 Absorption Spectroscopy;
 Electron Density (Concentration);
 Gas Ionization;
 Krypton;
 Molecular Relaxation;
 Shock Heating;
 Data Reduction;
 Gas Dynamics;
 Mathematical Models;
 MaxwellBoltzmann Density Function;
 Microwave Interferometers;
 Reaction Kinetics;
 Shock Tubes;
 Temporal Resolution;
 Atomic and Molecular Physics