Papers by Nikola Konjevic
Plasma Sources Science and Technology, 2020
Journal of Applied Physics, 2016
We present a simple one-dimensional iterative kinetic model of the cathode sheath region of high ... more We present a simple one-dimensional iterative kinetic model of the cathode sheath region of high voltage, low-pressure hydrogen hollow cathode discharge. The model's convenience as a supplemental diagnostic tool is demonstrated by determining the most relevant discharge parameters through an analysis of the spectral shape of the hydrogen Balmer alpha line recorded along the axis of a cylindrically symmetrical high voltage low-pressure hollow cathode glow discharge in hydrogen. Thus, an effectively one-dimensional approach is tested and shown to give satisfactory spectral lines fits with reasonable values for discharge parameters, most notably the gas temperature.
AIP Conference Proceedings, 1990
Experimental results of Stark broadening and shift of two neutral helium lines, 3889 and 5876 A, ... more Experimental results of Stark broadening and shift of two neutral helium lines, 3889 and 5876 A, in hydrogen-helium, pure helium and argon-helium plasmas are reported. Experimental Stark widths and shifts are compared with theoretical results obtained from three sets of semiclassical calculations of Stark-broadening parameters using quasistatic and ion-dynamic treatment of ions. Accounting for ion dynamics in the calculation of widths and shifts considerably improves the agreement between theory and experiments. The comparison shows a constant systematic descrepancy between the semiclassical calculations and experiment. These results suggest the feasibility of plasma-electron-density determination with a precision of 3--5%. A simple parametric expression that closely approximates the ion dynamic contribution to the shift of isolated lines is derived from the unified theory by Barnard, Cooper and Smith.
AIP Conference Proceedings, 2004
A short review of experiments dealing with excessive Doppler broadening of hydrogen and deuterium... more A short review of experiments dealing with excessive Doppler broadening of hydrogen and deuterium Balmer lines in various gas discharges is presented. Both old and new experimental data of excessive line broadening are discussed from the point of view of the collision model and the resonance transfer model. The results of several new experiments reported here, like the earlier ones, clearly support the collision model of excessive broadening.
Publications De L Observatoire Astronomique De Beograd, Nov 1, 1999
AIP Conference Proceedings, 1990
Systematic experimental and theoretical study of Stark broadening of BrI and II lines from (1D2)n... more Systematic experimental and theoretical study of Stark broadening of BrI and II lines from (1D2)np levels has been performed.
AIP Conference Proceedings, 2001
AIP Conference Proceedings, 2008
Stark broadened He I 447.1 nm line is measured and the dependence of the separation between its a... more Stark broadened He I 447.1 nm line is measured and the dependence of the separation between its allowed and forbidden components upon electron density is analyzed. Experimental results are compared with computer simulation results and with former experimental results.
Spectrochimica Acta Part B: Atomic Spectroscopy, 2014
We present the results of theoretical and experimental line shape study of the Li I 460.28 nm lin... more We present the results of theoretical and experimental line shape study of the Li I 460.28 nm line with a forbidden component in a low temperature laser-induced plasma. For this purpose a computer simulation method is used to calculate the overall line profile in the electron number density range of (0.5-11.0) × 10 16 cm-3 and the electron temperature 5800 K. The same computer simulation method is used to evaluate asymmetric profiles of the isolated Li I 497.17 nm line in the same electron density range and for several electron temperatures between 3500 K and 10300 K. The results for the Li I isolated line are used together with two other theoretical calculations for independent electron density measurements in laser induced plasma. The electron temperatures in the range of 4000-7000 K were determined from relative Li I line intensities using Boltzmann plot technique. The comparison between calculated profiles and experimental data for the Li I 460.28 nm line with a forbidden component indicates that theoretical results can be used for electron density diagnostics in the aforementioned density range with an accuracy of ±10-15%. To facilitate the application of theoretical line profiles simple expressions are supplied.
Xvii International Conference on Phenomena in Ionized Gases Held July 8 12 1985 in Budapest Hungary Contributed Papers Volume 1 Organizing Committee Icpig Xvii 1985 P 1010, 1985
Physical Review E, 1995
We report measured Stark shifts and widths of the neutral carbon 5052- and 4932-Å lines and the n... more We report measured Stark shifts and widths of the neutral carbon 5052- and 4932-Å lines and the neutral oxygen 4368-Å line in the plasma of an atmospheric pressure wall stabilized electric arc. Electron densities of (1.4-3.1)×1016 cm-3 are measured from the width of the Hbeta line while electron and gas temperatures in the range from 9300 to 10 300 K
The 14th international conference on spectral line shapes, 1999
We report the experimental Stark widths of plasma broadened lines belonging to 3s-3p and 3p-3d tr... more We report the experimental Stark widths of plasma broadened lines belonging to 3s-3p and 3p-3d transitions of singly and doubly ionized C, N and O emitters. The light source was a low pressure pulsed arc. The plasma electron densities were determined from the width of the Hell P{sub {alpha}} line while the electron temperatures were measured from the relative line intensities of five N II spectral lines.
The 14th international conference on spectral line shapes, 1999
The 14th international conference on spectral line shapes, 1999
Plasma broadened neutral atom spectral lines may be described by the convolution of Gaussian prof... more Plasma broadened neutral atom spectral lines may be described by the convolution of Gaussian profile (Doppler + instrumental broadening) and the Stark profile which is asymmetric, due to interaction between emitters and ions and can be well described by jA.R(TL) function defined as j'2.
The 14th international conference on spectral line shapes, 1999
Two volumes of the Bibliography on Atomic Line Shapes and Shifts have been published, in 1993 and... more Two volumes of the Bibliography on Atomic Line Shapes and Shifts have been published, in 1993 and 1998, by J. R. Fuhr and A. Lesage, covering the period from July 1978 up to now. Here, we will describe the progress made in the field during the past twenty years. In particular, we will focus, more particularly, on Stark broadening and on the reason why such parameters are important for stellar atmosphere opacity calculations. For recent work, we present an example, of the evaluation of experimental Stark widths and shifts of spectral lines of non-hydrogenic atoms and ions.
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Papers by Nikola Konjevic