Articles you may be interested inThe constricted glow discharge: A stationary source of vacuum-UV raregas excimer continua Rev. Sci. Instrum. 59, 565 (1988); 10.1063/1.1139834 Current density for cold cathode discharge gap in rare gasesThe macroscopic properties of the rare gas constricted discharges are discussed. For the rf excited discharge an equivalent circuit for the electrode coupling has been found, comprising a capacitor with the electrode and plasma forming the plates and the discharge tube wall the dielectric. An explanation for the observed striations is advanced, based upon the existence of voltage standing waves at the plasma resonance frequency. A numerical analysis based on an energy balance indicates that these discharges should have a finite radius, in this case smaller than the discharge tube radius. It is necessary to require that the electron energy distribution be Maxwellian near the center of the discharge and that deviation from this energy distribution causes the sharp boundary observed for the heavier rare gases. For the microwave discharge it is pointed out that it is necessary to include the electromagnetic field equations in the analysis and that this requirement naturally leads to a maximum radius for a single discharge channel which is much smaller than for the rf-excited case. This, in turn leads to an explanation of the multicolumn effect observed.

A description of the visual characteristics of some constricted discharges in the rare gases using dc, rf, and microwave excitation is given. These discharges require power inputs of from 20 to greater than 100 W/cc. The results of a series of spectroscopic and electrical measurements made on these discharges indicate the range of plasma parameters encountered. Gas temperatures were measured using the intensity distribution of the spectra of several diatomic molecules. The gas temperature falls in the range from 2000° to 3000°K, but atomic excitation levels are not in equilibrium at this temperature. The charge density is around 1014/cc from continuum intensity, line broadening, and electrical measurements. The electron energy distribution is Maxwellian with an average electron energy which falls between 1 and 2 eV. Thus, these plasmas lie between ``thermal'' and ``cold'' plasmas in their properties. The recombination process probably has contributions from both dissociative recombination and dielectronic recombination with an over-all recombination coefficient of about 2×10−11 cm3/sec.

Experimental and theoretical studies of the effect of mass on the dynamics of gas/organic-surface energy transfer

Three new heavy water rotational absorption lines have been observed in the microwave region. One of these lines and another line previously observed by McAfee have been identified as HDO lines by a study of the variation of their intensities with isotopic molecular concentration. By interpreting their Stark structure, the two HDO lines are assigned as follows: HDO:8−1→80 at 24 884.85 Mc/sec and HDO:6−2→7−6 at 26 880.47 Mc/sec. In addition, results on the Zeeman spectra of the two identified HDO lines are presented.

The frequency spectrum in the microwave region and the Stark effect are obtained for the case of a potential function with a high cis-peak and a low trans-peak. Using the presently available experimental data on H20, it is not possible to determine whether this potential function or the cis-peak equal trans-peak potential function is correct. It is shown, however, that the microwave data can answer this question if sufficient resolution is obtained.