Molar volumes and viscosities of LiClO4 and LiBr in propylene carbonate + 1,2-dimethoxyethane mixed solvents at 298.15 K

The standard partial molar volumes, viscosity B-coefficients and activation free energies of lithium salts (LiClO₄ and LiBr) in propylene carbonate (PC) with 1,2-dimethoxyethane (DME) mixed solvents have been determined as a function of the mole fraction of DME at 298.15 K from precise density and viscosity measurements. The values studied are all positive and decrease monotonously with addition of DME in the PC, which indicates that nature of the solvents plays an important role. The effects are discussed in terms of preferential solvation and packing effect in the solvation shell and electrostriction. The differences between ClO₄⁻ and Br⁻ have also been discussed.     

Surface plasmon resonance and electrochemistry for detection of small molecules using catalyzed deposition of metal ions on gold substrate

Small molecules are difficult to detect by conventional surface plasmon resonance (SPR) spectroscopy due to the fact that the changes in the refractive index resulted from the binding process of small biomolecules are quite small. Here, we report a simple and effective method to detect small biomolecule using SPR spectroscopy and electrochemistry by catalyzed deposition of metal ions on SPR gold film. As an example, the ascorbic acid-mediated deposition of Ag on gold film was monitored by in situ SPR spectrum. The deposition of Ag atom on gold film resulted in an obvious decrease of depth in SPR angular scan curves of reflectance intensity and minimum reflectivity angle. The depth change of the SPR reflectance intensity and minimum reflectivity angle curves mainly relied on the amount of Ag atom deposited on gold film that can be controlled by the concentration of ascorbic acid. By monitoring the deposition of Ag atom on gold film, ascorbic acid was detected in the concentration range of 2 × 10⁻⁵ M to 1 ×  10⁻³ M. After each of detections, the SPR sensor surface was completely regenerated by a potential step that stripped off the Ag atom. Furthermore, the regeneration process of the sensor surface provides the feasibility for detecting the concentration of ascorbic acid by electrochemical method.     

L X-ray emission from fast highly charged Cu ions in collisions with gaseous targets: Saturation effect in excitation and transfer

We have measured L X-ray production cross sections for highly charged 156 MeV Be-like Cu ions in collisions with gaseous targets of H₂, Ne, Ar, Kr and Xe. In the present collision systems, measured projectile L X-ray intensity is contributed by the excitation as well as electron transfer processes. The projectile L X-ray production cross sections are found to increase initially and then saturate with increasing target atomic number. The charge state dependence of projectile L X-ray production cross sections have been measured with Kr target.     

Intrinsic infrared absorption for carbon–fluorine bonding in fluorinated nanodiamond

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Chemistry and physics with many positrons

The first study of a high-density collection of positronium (Cassidy et al., 2005) revealed Ps–Ps spin exchange interactions in a porous silica sample. The prospects for further work in this field include forming di-positronium molecules and the Ps Bose–Einstein condensate, and constructing an annihilation gamma ray laser.     

Anti-solvent assisted treatment for improved morphology and efficiency of lead acetate derived perovskite solar cells

An efficient solution-processable route employing Pb(Ac)₂ as lead source and anti-solvent treatment to achieve fully covered and homogenous perovskite films is reported.     

Spectroscopic Studies on Charge Transfer from Ce^3＋ to Yb^3＋ in KMgF3 ： Ce, Yb Nanocrystals

Nanocrystals of KMgF3 single-doped and codoped with Ce^3＋ or/and Yb^3＋ were synthesized separately by the mi-croemulsion method. The X-ray diffraction（XRD） patterns were indexed to show that the KMgF3 crystal system was unchanged. The fluorescent spectra of KMgF3： Ce, Yb polycrystal powders were studied and compared with those of the Ce,Yb doped KMgF3 crystals produced using the high-temperature solid phase method. The diffuse reflection spectra and infrared emission of KMgF3： Ce, Yb were investigated. From the results, the authors could confirm that there were charge transfer processes from Ce^3＋ to Yb^3＋ in both KMgF3： Ce,Yb nanocrystals and polycrystal powders.     

DETERMINATION OF DEGREE OF CRYSTALLINITY OF NYLON 1212 BY WIDE-ANGLE X-RAY DIFFRACTION

Based on the X-ray scattering intensity theory and using the approximate expression for the atomic scattering factor, the correction factors for three crystalline peaks and an amorphous peak of Nylon 1212 were calculated and the formula of degree of crystallinity of Nylon 1212 was derived by a graphic multipeak resolution method. The degree of crystallinity calculated from the WAXD method is compatible with those obtained by density and calorimetry methods.     

Correlated intermolecular interaction components from asymptotically corrected Kohn-Sham orbitals

In these years there was considerable interest inunderstanding of intermolecular forces in energetic(explosive) systems[1—3]. The supermolecular approach(SM) is widely adopted for calculating ab initio in-termolecular interactions. Nevertheless, it is unable toprovide physically meaningful interaction contribu-tions such as electrostatic, induction, repulsion anddispersion energies. In contrast, the symmetry-adaptedperturbation theory (SAPT)[4—8] has the ability to de-rive these correlated…     

The high-temperature heat capacity of LnPO4 (Ln = La,Ce, Gd) by drop calorimetry

The high-temperature heat capacity of three lanthanide orthophosphates of monazite structure have been measured in the temperature range (450 to 1570) K. The data have been analysed in terms of a lattice term, represented by the 4f⁰ and 4f⁷ compounds LaPO₄ and GdPO₄, and an electronic term for CePO₄. The calculated excess heat capacity thus obtained is in reasonable agreement with that calculated from the crystal field energies.