Inner shell structure of heavy atoms

The inner-shell structure of some heavy atoms is examined using a self-consistent relativistic local density method. Ar(K), Kr(K) and Xe (K,L ₁,L ₂ andL ₃) binding energies and {ie863-1} (hyper-satellite) energies of Tl, Hg and Tm are calculated. The results are compared with available experimental data. A part of this work was presented byMPD at the Trieste International Symposium on “Core level excitations in atoms, molecules and solids,” 22–26 June 1981, Extended Abstracts (ed.) E Tosatti, ICTP Report No. 89/81 p. 11.     

Chemistry of azoimidazoles. Synthesis,spectral characterization and redox studies of N(1)-benzyl-2-(arylazo)imidazolepalladium(II)chloride

Arylazoimidazoles (2) are N,N-chelating ligands. The polymerization trend of the azolate system is restricted via N(1)-benzylation. The parent molecules (2), N(1)-benzylated products (3) and palladium complexes (4) were made by standard methods. The ligands (3) and complexes (4) are new. They have been characterized by elemental analysis, i.r., u.v.-vis. and high resolution 1H-n.m.r. spectral data. Redox studies were carried out by cyclic voltammetry. On complexation, azo reduction is shifted anodically.     

Polymerization of acrylonitrile. Kinetics of the reaction initiated by the Ce(IV)/thioacetamide redox system

Vinyl polymerization of acrylonitrile initiated by the Ce(IV)/thioacetamide redox system has been investigated in aqueous sulfuric acid in the temperature range of 10–20°C. The rate of polymerization (R_p) and the rate of Ce(IV) disappearance (?R_Ce) were measured. The effect of certain water-soluble organic solvents, added electrolytes, and aromatic and heterocyclic organic nitrogen compounds on the rate of polymerization has been investigated. Depending on the experimental results, we have suggested a suitable reaction scheme for the system which involves the production of initiating radicals from the oxidation of thioacetamide (TAm) by ceric ion and the termination of the polymer chain by metal ions.     

A classical description of deep inelastic collisions with surface friction and deformation

The friction model for heavy ion induced fusion and deep inelastic nuclear reaction is extended to include deformation. Spheroidal deformation and relative motion of the mass centres of the two interacting nuclei are treated as dynamical variables. The radial frictional force has been assumed to be proportional to the rate of change of the separation between the two surfaces instead of the two centres of mass. The friction coefficients remain unaltered. The potential as a function of deformation and separation distance are generated by a single folding procedure. The model is applied to⁴⁰Ar+²³²Th at 379 MeV (Lab) and¹³⁶Xe+²⁰⁹Bi at 1,130 MeV (Lab). In case of the former, the energy loss, which has not been properly accounted for before, is now satisfactorily explained and in the case of the latter the model predicts the absence of fusion in agreement with experiment.     

Rapid spectrophotometric determination of phenothiazines with molybdophosphoric acid

A simple and rapid spectrophotometric method for the determination of six phenothiazines can be based on the formation of a coloured compound between molybdophosphoric acid and phenothiazines. The i.r. and e.s.r. spectra of the coloured compounds showed that molybdophosphoric acid oxidizes phenothiazines to a radical cation with which it then forms a coloured compound. The proposed method is employed for the determination of phenothiazines in pharmaceutical preparations. Calibration graphs are linear over ranges of about 100–2000 μg of the phenothiazine.     

A characterization based on the equidistribution of the first two spacings of record values

Summary For a sequence {X _n:n=0, 1, 2,...} of i.i.d. discrete random variables let X ₀ denote the zeroeth record value and X _L(1), the first record value. It is shown that X ₀ and X _L(1) –X ₀ are identically distributed if and only if X ₀ has the geometric distribution over the lattice k :k=1, 2,... for some >0.     

Aqueous polymerization of acrylonitrile initiated by the bromate–thiourea redox system

The aqueous polymerization of acrylonitrile initiated by an acidified bromate–thiourea redox system has been studied under nitrogen atmosphere. The rate of polymerization is independent of thiourea concentration over the range 2–9 × 10^?3M and reaches maximum at 9 × 10^?3M. The rate varies linearly with [monomer]. The initial rate of polymerization as well as the maximum conversion increases within the range of 4–22.5 × 10^?3M KBrO₃, but beyond 22.5 × 10^?3M the rate of polymerization decreases. The initial rate and the limiting conversion increases with increasing polymerization temperature in the range 30–45°C; and beyond 45°C they decrease. The effect of certain neutral salts, water-soluble solvents, and micelles of cationic, anionic, and nonionic surfactants on the rate of polymerization has been investigated.     

Synthesis and characterization of styrene grafted carbon nanotube and its polystyrene nanocomposite

Effective side wall functionalization of single-walled carbon nanotube (SWCNT) with 4-vinylaniline was carried out through solvent free functionalization. The functionalized SWCNT was characterized through FT-IR and NMR. Typical peaks to identify the functionalization were observed. Thermal analysis shows around 48% weight loss in functionalized SWCNT in comparison to the pure SWCNT. The ratio of disordered to order transition (I_D/I_G) in FT-Raman, indicated the generation of some surface defects due to functionalization. Near infrared spectrum of functionalized SWCNT also confirmed the functionalization of SWCNT. The polystyrene nanocomposite materials were prepared with functionalized SWCNT as fillers by solution casting from tetrahydrofuran. The functionalized SWCNT nanocomposite showed significant improvement in mechanical properties and electrical properties. The dispersibility of the carbon nanotube in the composite was investigated by using scanning electron microscopy.     

A new method for determining the local environment and orientation of individual side chains of membrane-binding peptides

We studied here the binding of the mastoparan X peptide to a zwitterionic lipid bilayer (POPC) and demonstrated that nitrile-derivatized amino acids can be used to determine the hydration state (or change in hydration state) of specific sites of membrane-interactive peptides (upon binding). We have also shown that polarized ATR-FTIR measurements can further be used to uncover information regarding the spatial orientation of individual side chains as well as their conformational preference within the lipid bilayer.     

Energies of Charge Transfer for the Supramolecular Complexes of [60]- and [70]Fullerenes with a Series of meso-Tetraphenylporphyrins in the Solution State

Supramolecular complexes of [60]- and [70]fullerenes with various meso-tetraphenylporphyrins in toluene solutions have been studied by electronic absorption spectroscopy. Charge transfer (CT) absorption bands are observed in the visible region. Vertical ionization potentials (I _D ^V) of the meso-tetraphenylporphyrins are reported from a study of EDA interaction of these porphyrins with a number of electron acceptors like o-chloranil, p-chloranil, 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) and vitamin K. The dependence of the CT transition energy on the donor ionization potential has been utilized to estimate the vertical electron affinities (E _A ^V) of [60]- and [70]fullerenes in solution. The value of E _A ^V for [60]fullerene is found to be 0.10 eV lower in magnitude than that of [70]fullerene. We have extracted degrees of CT, and oscillator and transition dipole strengths of the fullerenes/meso-tetraphenylporphyrins complexes. The experimental results show that the CT complexes studied here have a neutral character in their ground states. Electronic coupling elements have been determined for fullerene/meso-tetraphenylporphyrin complexes. Values of the solvent reorganization energy indicate that the electron transfer process takes place at a faster rate in the case of [70]fullerene/meso-tetraphenylporphyrin complexes.