Investigation of electronic structure and associated nuclear quadrupole interaction of adsorbed fluorine atoms on silicon surface

The electronic energy levels and wave functions of fluorine and chlorine atoms adsorbed at the <111> surface of silicon are obtained by the Hartree-Fock procedure applied to clusters simulating the surface structure. Minimising the total energy with respect to the positions of the halogen atoms, the Si-Cl distance in the adsorbed system was found to be in good agreement with that from a recent SEXAFS measurement, there being no corresponding data presently available for fluorine on silicon surface. The calculated¹⁹ f ^* nuclear quadrupole coupling constants using the electronic wave functions for SiH₃F and the larger cluster Si₄H₉F, simulating the surface, differed substantially in contrast to the situation for the Si-F distance, indicating that the quadrupole coupling is a more sensitive indicator of the adequacy of the cluster chosen to represent the surface system. Experimental results for the coupling constants are awaited for comparison with theory.     

Synthesis and photoluminescence investigations of the white light emitting phosphor,vanadate garnet,Ca2NaMg2V3O12 co-doped with Dy and Sm

Vanadate garnet systems namely Ca₂NaMg₂V₃O₁₂, individually doped with Dy and Sm and also co-doped with both the RE ions were synthesized via the solid-state reaction route and their photoluminescence (PL) properties were investigated. The method of synthesis was verified by the formation of single phase compound through X-ray diffraction (XRD) studies. Existence of energy transfer in between the host and the dopant ions was established by PL investigation. Color coordinates of all the compounds were calculated and plotted on the CIE diagram. It was seen that the co-doped system has a near white light emission. It was concluded that this single phosphor is capable of converting the ultraviolet emission of a UV-LED into white light.     

Current perspectives on quinazolines with potent biological activities: A review

Quinazoline is a heterocyclic compound having biological activities. It is aromatic in nature having bicyclic structure containing benzene ring and pyrimidine ring. Quinazoline and its derivatives are found to have wide range of biological activities that is anticancer, analgesic, antimicrobial, antihypertensive, anticonvulsant, antimalarial, antitumor, and anti-tubercular activities. The purpose of this review is to highlight the recent researches made by researchers on various biological activities of quinazoline derivatives on different targets.     

Studies on stability of bi-functional P3HT:PCBM:rubrene optoelectronic devices

Investigations are carried out for stability in photovoltaic response of bifunctional electroluminescent and photovoltaic devices, based on ternary blend of poly(3-hexylthiophene) (P3HT), phenyl [6,6′]C₆₁ butyric acid methyl ester (PCBM), and 5,6,11,12-tetraphenylnaphthacene (rubrene). P3HT and PCBM are important and the most frequent materials used for photovoltaic applications, therefore, for relative comparison, photovoltaic cells were also prepared using a binary mixture of P3HT and PCBM. Devices based on the ternary blend exhibited better stability in all photovoltaic parameters and the lifetime was almost doubled, but their photovoltaic efficiency was lower than that of those based on the binary blend. Longer lifetime of ternary blend devices is because of a relatively better thermal, electrochemical, and morphological stabilities of the ternary blend system. However, the lower efficiencies are because of the reduced photo-current and low fill factor (FF) due to an increased recombination and introduction of defects/trapping sites by rubrene molecules.     

Recovery of plutonium and cerium from alumina crucible

Journal of Radioanalytical and Nuclear Chemistry - Plutonium recovery is inevitable from plutonium bearing alumina crucibles generated over the years as part of carbon analysis during chemical...