Molecular processes in expanding plasmas : a laser spectroscopic study

+74hlm.;24c

Atomic hydrogen and argon ground state density determination in a recombining plasma using visible light absorption spectroscopy

The atomic radical density in the first excited state, obtained by the technique of optical absorption spectroscopy, and a simple kinetic model are used to determine the radical ground state density in a recombining expanding plasma. The kinetic model used does not require knowledge of the shape of the electron energy distribution function. The information on electron density and electron temperature has been derived from the Thomson-Rayleigh scattering diagnostic. The method is demonstrated for the determination of the absolute ground state densities of atomic hydrogen H(n=1) and argon Ar(3p6) in a freely expanding plasma jet

Fabry-Perot line shape analysis on an expanding cascaded arc plasma in argon

Fabry-Perot line profile measurements have been used to obtain heavy particle temperatures and electron densities for as expanding cascaded arc plasma in argon. This was done for the argon 415.9 and 696.5 nm neutral lines as a function of the distance from the onset of the expansion. Temperatures in the range of 2000-12000 K were obtained. The electron density in the beginning of the expansion appeared to be 5.6*10/sup 21/ m/sup -3/. The 696.5 nm line profiles appeared to be asymmetric because of self-absorption by cool metastables around the plasma. The density and temperature of these metastables could be determined by fitting the measurements to a theoretical model, and appeared to be around 10/sup 17/ m/sup -3/ and around 3000 K, respectivel

The role of hydrogen during plasma beam deposition of amorphous thin films

The influence of wall-associated H/sub 2/ molecules and other hydrogen-containing monomers on the degree of ionization in the expanding thermal plasma used for the fast plasma beam deposition of amorphous hydrogenated carbon (a-C:H) and amorphous hydrogenated silicon (a-Si:H) was determined. Deposition models are discussed with emphasis on the specific role of the ion during deposition. The connection between the role of atomic hydrogen and the degree of ionization in the plasma beam deposition of a-C:H and a-Si:H is addresse