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Stark-width dependences on the upper-level ionization potential within different spectral series of neutral lithium have been studied and discussed. Similar dependences have been found for electron- and proton-impact contributions to the Stark widths. The emphasis is on the term structure influence on the studied Stark-width dependences. The effect of series merging with increasing temperature was found. Some lines with deviations from the corresponding series dependences can be explained by the absence of close perturbing states to the transition states. After establishing these dependences, the relations found were used for Stark-width prediction of the missed lines, thus avoiding much more complicated calculation procedures. [ABSTRACT FROM PUBLISHER]

ABSTRACT Stark width experimental and theoretical data of neutral helium spectral lines have been used to demonstrate their dependence on the upper-level ionization potential within different spectral series. The emphasis is on the term describing structure influence on the studied Stark-width dependences. After establishing these dependences, predictions were made for electron, proton and ionized helium impact contributions to the Stark widths of neutral helium spectral lines that have not been measured experimentally or calculated theoretically until now (transitions from high levels of He i). The accuracy of the data obtained is comparable with the accuracies of the experimental and theoretical values used in establishing the dependences. [ABSTRACT FROM AUTHOR]

Abstract: Periodic submicron cylindrical structures (SCS) produced in a single pulse treatment of silicon single crystal by supersonic compression plasma flow have been studied. The nitrogen quasistationary plasma flow generated by magnetoplasma compressor is used for modification of Si (100) surface. SCS have been analyzed using optical microscopy, scanning electron microscopy and atomic force microscopy. Typical species of cylindrical structures formed at the silicon surface have been discussed. These structures are induced by the plasma flow action and then quenched from the molten state during fast cooling and resolidification. SCS have been compared to periodical silicon surface structures made by plasma, ion beams and laser interaction with silicon. [Copyright &y& Elsevier]

Oriented submicron cylindrical structures obtained in a single pulse treatment of silicon monocrystal by compression plasma flow are described. The nitrogen plasma flow generated by magnetoplasma compressor is used for modification of Si (1 1 1) monocrystal surface. The speed of plasma flow was up to 40 km/s depending on input energy and gas used and its pressure. The electron density and temperature within the region of plasma flow maximal compression was up to 2×1017 cm−3 and 20,000 K, respectively. Silicon samples placed perpendicular to the flow were exposed to a single 100 μs plasma pulse driven by the discharge current of 70 kA. Typical dimensions of cylindrical structures formed at the crystal surface are 0.1–2 μm in diameter and up to 200 μm in length. The influence of external magnetic field on the dimensions of the cylindrical structures was also investigated. The large diameter cylindrical structures have been noticed to exhibit the hollow features. The catalyst was not used in the process of silicon surface modification. [Copyright &y& Elsevier]