On γ-ray laser

Abstract

We review various possibilities for realizing a y-ray laser. We conclude that, similar to the free-electron laser, it is practical to generate the y-ray laser by the stimulated emission of radiation from wiggling positrons channelled in a periodically bent crystal. It is the time to research this possibility both theoretically and experimentally with big efforts.

Theoretical calculations of transition probabilities for individual and multiplet lines between some excited levels of atomic potassium

“…Lavin et al [11] have calculated oscillator strengths for transitions in the diffuse spectral series of some members of the potassium iso-electronic sequence K I through Cr IV using the quantum defect orbital method, including core polarization. Recently, Zheng and co-workers have improved and employed the weakest bound electron potential model theory (WBEPMT) to determine various physical parameters in both alkali-metal atoms and other many electron atomic or ionic systems [12][13][14][15]. They have obtained very satisfactory results consistent with theoretical or experimental data in the literature for calculations of spectroscopic data.…”

“…In this work, we have employed the WBEPM theory for the determination of radial transition integrals. This theory was developed by Zheng [12] and has been applied to calculate various atomic properties such as energy levels, ionization potentials, transition probabilities, oscillator strengths, and the lifetimes of excited levels (see Zheng and co-workers [13][14][15]17]). This method is based mainly on the distinction of the weakest bound electron (WBE) and nonweakest bound electrons (NWBE) in a given atomic or ionic system.…”

Determination of Trace Metals in the Bark Root of Phyllanthus emblica (L

“…For example, zinc, iron, cobalt, chromium, copper and manganese are essential, while cadmium, lead, mercury are toxic 14 . In past few years research of trace element distribution in medicinal plants [15][16] becomes important. Trace elements are the essential for human health and they prevent several diseases.…”

Oscillator Strengths for Allowed Transitions in Li(II)

“…By the separation of the electrons in a given system, complex many-electron problem can be simplified as the single electron problem and so can be solved easily. This theory has been developed by Zheng [20,21] and has been applied to calculate various atomic properties such as energy levels, ionization potentials, transition probabilities, oscillator strengths and lifetimes of excited levels in the many-electron atomic and ionic systems [22][23][24][25][26]. In the WBEPM theory, electronic radial wave functions are presented as a function of the Laguerre polynomial in terms of some parameters which are determined using the experimental energy data and the expectation values of radii [22][23][24][25][26],…”

“…In the determination of Z * , n * and l * parameters, relevant energy values have been taken from experimental energy data in the literature and expectation values for the radii of levels have been calculated by using wave functions obtained from two different theoretical approximations. The papers given by Zheng et al describe in detail the WBEPM theory [20][21][22][23][24][25][26].…”