Kinetic energy release for the collision-induced dissociation of CO<Superscript>+</Superscript>

The kinetic energy release distributions (KERDs) of C⁺ and O⁺ fragments arising from 5 keV collision-induced dissociation (CID) of CO⁺ ions with helium have been measured. The KERDs of C⁺ and O⁺ exhibit different features corresponding to the states that participate in CID processes. We have identified groups of dissociative and predissociative states, and compare them with theoretical and experimental values.     

Relative acidities and structure analysis of cis and trans isomers of 1,5‐oxazaspiro[5.5] undecane derivatives by multinuclear magnetic resonance

The relative acidities of the cis and trans isomers of a series of 1,5‐oxazaspiro[5.5]undecane derivatives were determined by measuring ΔpK in acid‐base titrations followed by ¹ H NMR. Relative structural stabilities were determined by measuring substituent chemical shift and γ‐gauche effects in ¹³C, ¹⁵N, and ¹⁷O NMR. Crystallographic characterization of a model spiro[5.5]undecane is presented to support the basicity in solid state. Copyright © 2010 John Wiley & Sons, Ltd.     

Experimental characterisation, optimisation and design of erbium-doped silica fibre lasers

A new characterisation method is described using the new theoretical model for erbium-doped silica fibre lasers (EDSFLs) based on the energy conservation principle. Using this method, we obtained absorption and emission coefficients for the lasing wavelength at lasing operating conditions. After that, an experimental procedure to deduce the spectral profiles of the absorption and emission coefficients is also presented. This procedure allows us to obtain the values of these parameters for the whole fluorescence spectrum through measurements of gain profiles under the lasing operation. Once the absorption and emission coefficients are known, the new model can be applied and a comparison with experimental results for two different laser configurations is shown. The theoretical model is proved to be accurate and in addition some equations are developed to allow the design and optimisation of EDSFLs. This revised version was published online in March 2005. In the previous version, the published online date was missing     

Synthesis,characterisation and crystal structure of a cobalt(II)-hexamethylenetetramine coordination polymer

A novel one-dimensional zigzag coordination polymer, dinitrodiaqua-bis(hexamethylenetetramine)cobalt(II) was synthesised and characterised, and the structure was determined by single-crystal X-ray diffraction. The compound has a chain structure with each cobalt atom covalently bonded to two nitrate ions, two water molecules and two HMTA molecules, giving a slightly distorted octahedral geometry about the cobalt atom. Each HMTA ligand uses two of its N atoms to bond to two cobalt atoms giving an approximately bent Co–HMTA–Co configuration. Each chain is hydrogen bonded through OH···N and OH···O interactions with neighbouring chains leading to an overall polymer structure. Thermal studies show significant mass loss corresponding to the loss of the coordinated water molecules and the decomposition of both the nitrate ions and the HMTA.