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The vaporization of condensed materials in contact with high-current discharge plasmas is considered. A kinetic numerical method named direct simulation Monte Carlo (DSMC) and analytical kinetic approaches based on the bimodal distribution function approximation are employed. The solution of the kinetic layer problem depends upon the velocity at the outer boundary of the kinetic layer which varies from very small, corresponding to the high-density plasma near the evaporated surface, up to the sound speed, corresponding to evaporation into vacuum. The heavy particles density and temperature at the kinetic and hydrodynamic layer interface were obtained by the analytical method while DSMC calculation makes it possible to obtain the evolution of the particle distribution function within the kinetic layer and the layer thickness.

A laser induced fluorescence technique (LIF) in combination with optical emission spectroscopy (OES) and Rayleigh scattering (RS) was applied to investigate absolute number densities of the population of the three nitrogen triplet states C^3Πu, B^3Πg, and the metastable A^3Σ u+ in an asymmetric low pressure rf discharge. Primary targets of this investigation were the three lowest vibrational levels (v = 0,1,2) of each triplet state and additionally v = 8 of A^3Σu+ which can be populated very efficiently in the plasma sheath. Calibration of LIF intensities to absolute densities of A^3Σu+ and B^3Πg has been realized by comparison with the signal of the RS experiment done in pure nitrogen gas. Calibration of C^3Πu which we could not detect by LIF but rather only by OES was achieved after comparing OES and LIF signals of the B^3Πg state. Excitation energies of the analyzed states range from 6 up to 11.5 eV and the measured number densities differ by about seven orders of magnitude from as much as 1012 cm?3 down to almost 105 cm?3. In addition to the interpretation of the results this article describes the used calibration methods which are partly based on a suggestion made by P. Bogen (Proceedings of the XVI International Conference on Phenomena in Ionized Gases, Invited Papers, edited by W. Botticher, H. Wenk, and E. Schultz-Gulde, Dusseldorf, 1983, pp. 164-173).

Methods to chemically passivate the surfaces of amorphous-carbon films (a-C) produced by dc magnetron sputtering were studied. The chemical composition of carbon surfaces produced via sputtering are dependent upon the environment to which the carbon is exposed immediately following deposition. When the sputtered film is vented to ambient conditions, free radicals produced at the surface during the deposition process are quenched by reaction with oxygen and/or water to form an oxidized, hydrophilic surface. If the sputtered carbon film is, however, exposed to a reactive gas prior to venting to ambient, the chemical nature of the resulting surface can be modified substantially. Specifically, a less highly oxidized and much more hydrophobic carbon surface is produced when the surface free radicals are quenched via either an addition reaction (demonstrated with a fluorinated olefin) or a hydrogen abstraction reaction (demonstrated with two alkyl amines). Chemical modification of amorphous-carbon films can also be accomplished by performing the sputtering in a reactive plasma formed from mixtures of argon with molecular hydrogen, amines, and perfluorocarbons. The elemental composition of these films, and the relative reactivity of the surfaces formed, were investigated via x-ray photoelectron spectroscopy and contact-angle goniometry, respectively. In the case of sputtering with a mixture of argon and hydrogen, increasing the hydrogen flow results in an increase in the amount of hydrogen incorporated into the carbon film and a decrease in the surface free energy. Sputtering in diethylamine produces an amorphous-carbon film into which nitrogen is incorporated. The free energies of the a-C:N surfaces produced in this process are similar to those of the a-C:H films. Sputtering in a fluorocarbon vapor results in the incorporation of fluorine into the film structure and the formation of very low free-energy surfaces. Increasing the concentration of the fluorocarbon in the sputtering plasma increases the amount of F incorporated into the film. At the highest fluorocarbon flow rates employed, a-C films were produced with stoichiometries and surface free energies comparable to those of bulk Teflon.