Internal energy content of n-butylbenzene, bromobenzene, iodobenzene and aniline molecular ions generated by two-photon ionization at 266 nm. A photodissociation study

A technique to investigate photodissociation kinetics on a nanosecond time scale has been devised for molecular ions generated by multiphoton ionization (MPI) using mass-analyzed ion kinetic energy spectrometry. The branching ratio or rate constant has been determined for the photodissociation of the n-butylbenzene, bromobenzene, iodobenzene, and aniline molecular ions generated by MPI at 266 nm. The ion internal energies have been estimated by comparing the measured kinetic data with the previous energy dependence data. The analysis has shown that only those molecular ions generated by two-photon ionization contribute to the photodissociation signals. Around half of the available energy has been found to remain as molecular ion internal energy in the two-photon ionization process. Copyright 1999 John Wiley & Sons, Ltd.     

Dehalogenation of α -haloketones and vic-dibromides with nickel boride

α-Haloketones and $\text{vic}$-dibromides are converted to the corresponding ketones and alkenes respectively with nickel boride generated $\text{in situ}$ from sodium borohydride and nickel chloride.     

Conductivity of β″ and ion rich β alumina.I.H.+(H2O)n compounds

The conductivity and thermal stability of H⁺(H₂O)_n β″ and ion rich β alumina single crystals have been measured by the complex impedance method in the 25–700°C temperature range. Two mechanisms of conductivity were assumed: proton transfer at lower temperatures and H₃O⁺ diffusion in the high-temperature range. Both structures have similar properties, but ion rich β alumina possesses the best stability and the lowest activation energy (β: 0.15 eV, β″: 0.20 eV below 400 and 300°C respectively). The room-temperature conductivity is ≈5×10^?6 Ω^?1 cm^?1. The conducting properties and mechanisms are discussed and compared to other protonic or ionic conductors.     

New mass spectrometric approaches to structural analysis in mixtures

Structural analysis of minor components in mixtures is a vital requirement in the development of any pharmaceutical compound. Mass spectrometry is uniquely able to give this kind of information on the trace amounts of material present as minor impurities in a drug substance. In this study we show that a combination of mass spectrometric analysers with different characteristics is an even more powerful approach with a higher chance of establishing a potential structure. In particular the advent of analysers capable of accurate mass measurement on small amounts of material has enabled structures to be proposed in situations where previously no real conclusions could be made. Copyright 1999 John Wiley & Sons, Ltd.     

Rational matrix approximation with a priori error bounds for non-symmetric matrix Riccati equations with analytic coefficients

In this paper the exact solution of the non-symmetric matrixRiccati equation with analytic coefficients is approximatedby a rational matrix function with a prefixed accuracy. Thisrational matrix function is locally defined as the exact solutionof a Riccati problem with matrix polynomial coefficients obtainedby truncation of the Taylor expansions of the matrix coefficientsof the original problem.