IDEN2 - A program for visual identification of spectral lines and energy levels in optical spectra of atoms and simple molecules
Abstract The article describes a Java program that can be used in a user-friendly way to visually identify spectral lines observed in complex spectra with theoretically predicted transitions between atomic or molecular energy levels. The program arranges various information about spectral lines and energy levels in such a way that line identification and determination of positions of experimentally observed energy levels become much easier tasks that can be solved fast and efficiently. Program summary Program title: IDEN2 Program Files doi: http://dx.doi.org/10.17632/mwr2tk84sw.1 Licensing provisions: GPLv3 Programming language: Java v.1.8 Nature of problem: Line identification problem in atomic and molecular spectra that have a limited number of previously known low-excited energy levels and a large number of unidentified spectral lines (emission or absorption). The line identification consists of finding the lower and upper energy levels of transitions corresponding to each observed spectral line. Solution method: For each energy level (experimentally known or unknown), the list of observed spectral lines is displayed on a wavenumber scale as an image. This image is repeated with certain vertical shifts in several columns corresponding to other levels connected with the investigated one by theoretically predicted transitions. In each such column, the image of the line spectrum is shifted by the value corresponding to the energy of the connecting level. Then the problem of location of an unknown level is reduced to scrolling the screen until several spectral lines in different columns align along the same horizontal line. Various gadgets provide complete information about all pertinent entities, such as the level identities, wavelengths, observed and calculated intensities. Additional comments including restrictions and unusual features: A practical limitation on the size of the problem is imposed by the available RAM, which is typically sufficient to treat spectra with up to 100 000 spectral lines and 10 000 energy levels. The visual appearance of all gadgets, including font sizes, colors, and window sizes and positions, is completely customizable. An extensive Help system and User Guide are included.
The Third Spectrum of Tantalum (Ta III): Fine and Hyperfine Structure
Presented is the first successful analysis of the Ta III spectrum. All the 37 levels of the low lying even configurations 5d3, 5d26s, and 5d6s2, and all the 68 levels of the higher odd configurations 5d26p and 5d6s6p have been established. About 720 spectral lines have been classified in the region of 1000–3950 A as belonging to the (5d3 + 5d26s + 5d6s2) - (5d26p + 5d6s6p) transition array. The results are mainly based on spectrograms obtained by means of a vacuum sliding spark discharge and a 10.7 m normal incidence spectrograph at the Paris-Meudon Observatory, which provides a unique plate factor of 0.25 A/mm in the first order. The resulting line list has been completed by partial data taken from earlier lists used for the Ta II and Ta IV studies. The analysis was guided by predicted energy level values and transition probabilities calculated by means of a complete set of orthogonal operators. The program suite IDEN for computer-aided spectra analyses played a crucial role in the study. The list of classified spectral lines and derived energy level values are presented. Calculated energy values and Lande factors, LS-compositions and gA-values, obtained from the final fitted parameter values using the orthogonal operator approach are also given. A few lines have partially resolved hyperfine structures owing to the high dispersion of the Meudon spectrograph. They connect levels with an unpaired 6s electron. The iso-nuclear trends of the a6s hfs parameter are straight from Ta I to Ta III.
Microwave source with enhanced radiation power based on orbitron MASERs
We have proposed the design of high power microwave source in a vacuum tube based on the theory of negative mass instability. The proposed source does not operate based on a slow-wave structure but instead makes use of accelerated charged particles. In our structure, an electron emitter injects the charged particles into to the cavity. Emitted particles move around the anode, which leads to electron acceleration and emission of electromagnetic waves with a specific frequency. In this paper, we have enhanced the output power and frequency of microwave source by variation of particles initial energy and the number of anodes incorporating their specific arrangement and applied voltages. Working at room temperature, compactness, wide bandwidth, and tunability of output frequency are among the advantages of the proposed source.