Comparison of AB2 and AB4 monomers in ferrocene-cored benzyl ether dendrimers

Ferrocene-cored unsymmetric and symmetric arylalkyl ether dendrimers based on an AB₂ monomer (3,5-dihydroxybenzyl alcohol) were prepared. Their electrochemical properties were compared with the unsymmetric and symmetric ferrocene-cored dendrimers based on a relatively rigid and three-dimensionally disposed AB₄ monomer. The thermodynamics and kinetics of heterogeneous electron transfer in these dendrimers show that G_2n of AB₂ dendrimers behave similar to G_n of AB₄ dendrimers. For example, the redox reaction shows significant irreversibility especially at higher scan rates in the case of G₄ didendron based on AB₂ monomer and G₂ didendron based on AB₄ monomer. Despite the fact that AB₄ building blocks are more rigid, the effective encapsulation in both these dendrimers are similar. This result is attributed to the three dimensional disposition of the branching points in the AB₄ monomer.     

A Tauberian theorem for weighted means in non-archimedean fields

In this note, K denotes a complete, non-trivially valued, non-archimedean field. We prove a Tauberian theorem for weighted means in K.     

Calculation of force constants and mean amplitudes of vibration of octahedral XY6 molecules using frequencies and zeta constants

Expressions involving vibrational frequencies, Coriolis coupling constants and masses of the atoms of the molecule that are invariant under symmetrical isotopic substitutions are derived for octahedral XY₆ molecules following the method given by Jagannathan and others. These invariants are used to calculate the force constants, compliance constants and mean amplitudes of vibration of 13 molecules of XY₆-type.     

Spin-polarized relativistic calculations on highly ionized molybdenum

The energies of K_α X-ray satellite lines of molybdenum ionized to different degrees in the L shell with closed and open outer shells (n=3,4 and 5) are reported in this work. The calculations have been carried out using Xα method with spin-polarized single configuration relativistic Dirac-Fock wavefunctions. Calculations have also been carried out with un-polarized relativistic wavefunctions. The effect of relativistic spin exchange potential on the total energies of the various states ionized to different degrees in the inner and outer shells are analyzed. As the transition assignments in the spin-polarized treatment of atomic orbitals take into account the spin orientations of the electrons in the initial and final states, the present calculations elucidate the significance of this technique in giving unique spin-dependent transition assignments to experimental energies.     

Photochemical reduction of uranyl ion in nitric acid medium using a XeCl excimer laser

This paper describes the results of photoreduction of uranyl (UO₂ ²⁺) ion to U⁴⁺ in 0.2M HNO₃ and ethanol using a 308 nm XeCl excimer laser. The effects of different concentrations of ethanol and the addition of sulfamic acid on the quantum yield for U⁴⁺ formation are discussed.