Cerium, the most abundant rare earth element, and boron containing mineral (lithium tetraborate pentahydrate) were used for synthesizing rare earth borates. Alternatively, for preparing rare earth borates, hydrothermal technique can be used. The non-stoichiometric cerium and boron containing compounds were synthesized by hydrothermal method using cerium sulphate and lithium tetraborate pentahydrate in appropriate molar ratio. Characterizations were done by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive X-ray analysis, and thermogravimetric/differential thermal analysis.
Electric dipole oscillator strengths have been computed for transitions between both multiplet and individual lines in the Li(II) ion. The weakest bound electron potential model theory has been used. We have employed both numerical Coulomb approximation wave functions and numerical non-relativistic Hartree-Fock wave functions in the determination of expectation values of radii. The necessary energy values have been taken from experimental ionization energies. The oscillator strengths calculated with parameters obtained by using the two different wave functions have been compared not only to each other but also to other data taken from literature. A good agreement with results in literature has been obtained.
CeVO_4 (ICDD: 12-757) was synthesized by microwave-assisted method by using cerium sulphate and vanadium (V) oxide in an appropriate molar ratio. Characterizations were done by X-ray diffraction, Fourier transform infrared spectroscopy, ultraviolet spectrophotometry and thermogravimetric/differential thermal analysis. The material is crystallized in tetragonal system with unit cell parameters a = 7.399 Å and c = 6.496 Å and space group I41/amd(141).
Transition probabilities are calculated for individual and multiplet lines between some excited states in neutral sodium by using the weakest bound electron potential model theory. In the determination of parameters required for calculation of transition probabilities, we employed numerical non-relativistic Hartree-Fock wave functions for expectation values of radii in all levels. The necessary energy values were taken from experimental energy data in the literature. The obtained results were compared with accepted values taken from National Institute of Standards and Technology data and multi-configurational Hartree-Fock results given by Fischer. A good agreement was observed in related excited states.
The theoretical lifetimes for singly ionized beryllium (Be II) have been calculated using the weakest bound electron potential model theory and the quantum defect orbital theory under the assumption of the LS coupling scheme. In the calculations, many states are considered. Some lifetime values for highly excited levels have been obtained using these methods. The lifetimes presented in this work have been compared with the early theoretical calculations and measurements presented in the literature. A good agreement with the results in the literature has been obtained.
In this work, the theoretical calculation of excited-state ionization potentials for 1s^22_p ^2P_{1/2}, 1s^23_s^2S_{1/2}, 1s^23_d^2D_{1/2}, 1s^24_s^2S_{1/2}, 1s^24_p^2P_{1/2}, and 1s^24_d^2D_{1/2} iso-spectrum series of lithium-like elements were carried out using a weakest bound electron potential model theory for nuclear charges from Z=3 to Z=18. The Breit-Pauli approximation was used for relativistic contributions. The obtained values are compared with the experimental results from literature. The overall agreement between data obtained in this work and experimental data from literature can appear to be quite good being generally within 0.1% of experimental values.
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