Measurement of Lα/Lℓ, Lα/Lβ and Lα/Lγ X-ray intensity ratios for elements in the atomic range 57⩽Z⩽92 using radioisotope X-ray fluorescence

Lα/Lℓ, Lα/Lβ and Lα/Lγ intensity ratios have been measured for some elements with atomic range 57⩽Z⩽92 by using characteristic L X-rays from targets excited by 59.54 keV photons from a filtered radioisotope ²⁴¹Am point source. Theoretical values of the Lα/Lℓ, Lα/Lβ and Lα/Lγ intensity ratios were calculated using theoretically tabulated values of subshell photoionization cross-sections, fluorescence yields, fractional X-ray emission rates, Coster–Kronig transition probabilities. Experimental results have been compared with the theoretical values and other available experimental results. Good agreement was observed between experimental results, other available experimental results and theoretically calculated values.     

A Molecular Dynamics study of the influence of side-chain length and spacing on lithium mobility in non-crystalline LiPF6·PEOx; x = 10 and 30

Molecular Dynamics (MD) simulation techniques have been used to investigate systematically how the length and spacing of poly(ethylene oxide) (PEO) side-chains along a PEO backbone influence ion mobility for two different salt concentrations. This is of fundamental relevance to the design of new polymer electrolytes for battery applications. The salt used has been LiPF₆ in concentrations corresponding to Li:EO ratios of 1:30 and 1:10. The MD box contained PEO backbones of 89–343 EO units to which 3, 6, 7, 8, 9 and 15 EO unit side-chains were added. The selected spacings along the backbone between the PEO side-chains attachment points were 5, 10, 15, 20 and 50 EO units. The backbone and all side-chains were methoxy end-capped, and the simulations were all made at 293 K. Ion mobilities have been estimated from the variation of mean-square-displacement with time, and have been analysed in relation to chain dynamics, cross-linking and ion pairing. Comparisons are also made with the results of simulated PEO systems without side-chains and/or without salt. It is found that, at a higher concentration, many short side-chains give the highest ion mobility, while the mobility is highest for side-chain lengths of 7–9 EO units at the lower concentration.     

The influence of Zn2+ ion on the 1.5 μm laser properties of LiNbO3 crystal heavily doped with Er3+ ion

The spectral characteristics of 1.54 μm emission in a series of Zn/Er:LiNbO₃ crystals with heavy Er content and variable Zn content were reported. The inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the concentration of Er³⁺ ion in the crystal. The absorption and emission spectra of Zn/Er:LiNbO₃ crystals were measured. Based on Judd–Ofelt theory, the spectral parameters such as intensity parameters Ω_t (t=2, 4 and 6), transition strengths, radiative transition probabilities, radiative lifetime and fluorescence branching ratio have been obtained in Zn/Er:LiNbO₃ system. The emission cross section corresponding to ⁴I_13/2→⁴I_15/2 transition of Er³⁺ ion was obtained according to Füchtbauer–Ladenburg theory. The gain cross section of Er:LiNbO₃ crystal codoped with 6 mol% Zn²⁺ ions were also discussed in this work.