B.K. Sen

Bio: B.K. Sen is an academic researcher. The author has contributed to research in topics: Proton transport & Proton. The author has an hindex of 1, co-authored 1 publications receiving 4 citations.

Mechanism of proton transport in HUP (HUO2.PO4.4H2O)

Abstract: Existing theories for the mechanism of proton transport in HUP has been considered and their limitations discussed. The crystal structure of the material has been examined. The transport of protons from one water square to another might take place through the participation of the pi-charge cloud of the phosphate group. A suitable rotation of the water molecule provides the continuous proton pass. The variation of conductivity with temperature and pressure have been interpreted.

Density functional theory study of the complexation of the uranyl dication with anionic phosphate ligands with and without water molecules.

Abstract: The structures, vibrational frequencies and energetics of anhydrous and hydrated complexes of UO22+ with the phosphate anions H2PO4–, HPO42–, and PO43– were predicted at the density functional theory (DFT) and MP2 molecular orbital theory levels as isolated gas phase species and in aqueous solution by using self-consistent reaction field (SCRF) calculations with different solvation models. The geometries and vibrational frequencies of the major binding modes for these complexes are compared to experiment where possible and good agreement is found. The uranyl moiety is nonlinear in many of the complexes, and the coordination number (CN) 5 in the equatorial plane is the predominant binding motif. The phosphates are found to bind in both monodentate and bidentate binding modes depending on the charge and the number of water molecules. The SCRF calculations were done with a variety of approaches, and different SCRF approaches were found to be optimal for different reaction types. The acidities of HxPO43-x in ...

Excited-state properties of lamellar solids derived from metal complexes and hydrogen uranyl phosphate

Abstract: Hydrogen uranyl phosphate (HUP), HUO 2 PO 4 ·4H 2 O, is a layered solid that undergoes intercalative ion-exchange reactions with guest cationic species spanning the periodic table. The host lattice exhibits highly efficient green photoluminescence (PL) characteristic of the uranyl (UO 2 2+ moiety. Structural and optical perturbations of the host and guest generally accompany intercalation reactions. Guest metal complexes have afforded an opportunity to study host-to-guest energy transfer, interlamellar acid-base/precipitation chemistry, interlamellar redox chemistry, and host lattice substitution chemistry. These reactions are summarized in this article.

Reliable predictions of the properties of actinide complexes

Abstract: ................................................................................................................................... ii DEDICATION ............................................................................................................................... iv LIST OF ABBREVIATIONS AND SYMBOLS ............................................................................v ACKNOWLEDGMENTS ...............................................................................................................x LIST OF TABLES .........................................................................................................................xv LIST OF FIGURES ................................................................................................................... xviii CHAPTER

Time-resolved luminescence studies in hydrogen uranyl phosphate intercalated with amines

Abstract: Time-resolved luminescence decays of intercalated compounds of hydrogen uranyl phosphate (HUP) with p-toluidinium (HUPPT), benzylaminium (HUPBZ), α–methylbenzylaminium (HUPMBZ) and hydroxylaminium (HUPHAM) were studied. The prepared compounds belong to the tetragonal P4/ncc space group and showed 00 l reflections shifted to lower angles relative to HUP, indicating that the intercalation increases the c parameter of the unit cell. The luminescence decays of the compounds with 100% of intercalation ratio (HUPHAM and HUPBZ) were analyzed by Global Analysis, assuming Lianos’ stretched exponential as the model function, which can be applied to compounds with restricted geometry and mobile donor and quencher molecules. It was remarkable that the luminescence decays showed that the quenching of the emission of the uranyl ions by the intercalated protonated amines is not restricted by low dimensionality of the host uranyl phosphate, and that a diffusion mechanism occurs. Benzylaminium cation efficiently quenches the excited energy of the uranyl ions at close distance, but the long-range and long-lifetime quenching is hindered. A different situation is found in the case of the small hydroxylaminium cation, where the long distance diffusion of the species is fast, playing an important role in the quenching of the excited uranyl ions at longer times.