Vector tadpole graphs in the Coleman-Weinberg model

In the Coleman-Weinberg model (massless scalar quantum electrodynamics), a gauge invariant approximation scheme is obtained by summing vector tadpole graphs to all loop orders. We investigate the influence of this summation on the masses of the scalar and vector particles in the model.     

Analysis of microwave and infrared transitions of phenol by rotation-internal rotation theory. Phenol-OD

Rotational transitions of the torsional ground and first excited state of phenol-OD have been measured in the frequency range 8–40 GHz. In a semi-rigid model approach to the internal rotation, kinetic and potential constants have been fitted to the far-infrared torsional frequencies and the microwave transition frequencies for the ground and the excited state separately. It is further shown that an acceptable agreement between observed and calculated spectra has simultaneously been obtained for the torsional ground and first excited state using the contravariant kinetic coefficients g^mn as fitting parameters.     

Fluoride‐Bridged {GdIII3MIII2} (M=Cr,Fe, Ga) Molecular Magnetic Refrigerants

The reaction of fac‐[M^IIIF₃(Me₃tacn)]⋅x H₂O with Gd(NO₃)₃⋅5H₂O affords a series of fluoride‐bridged, trigonal bipyramidal {Gd^III₃M^III₂} (M=Cr ( 1 ), Fe ( 2 ), Ga ( 3 )) complexes without signs of concomitant GdF₃ formation, thereby demonstrating the applicability even of labile fluoride‐complexes as precursors for 3d–4f systems. Molecular geometry enforces weak exchange interactions, which is rationalized computationally. This, in conjunction with a lightweight ligand sphere, gives rise to large magnetic entropy changes of 38.3 J kg⁻¹ K⁻¹ ( 1 ) and 33.1 J kg⁻¹ K⁻¹ ( 2 ) for the field change 7 T→0 T. Interestingly, the entropy change, and the magnetocaloric effect, are smaller in 2 than in 1 despite the larger spin ground state of the former secured by intramolecular Fe–Gd ferromagnetic interactions. This observation underlines the necessity of controlling not only the ground state but also close‐lying excited states for successful design of molecular refrigerants.     

Highly Efficient One-Step Conversion of Selenol Esters into Symmetrical Diselenides in the Presence of Elemental Iodine in Methanolic Solution

A facile, efficient, and convenient procedure has been developed for the direct conversion of selenol esters into the corresponding diselenides in the presence of elemental iodine at room temperature.     

Simple loop conjecture for limit groups

There are noninjective maps from surface groups to limit groups that don’t kill any simple closed curves. As a corollary, there are noninjective all-loxodromic representations of surface groups to SL(2, ?) that don’t kill any simple closed curves, answering a question of Minsky. There are also examples, for any k, of noninjective all-loxodromic representations of surface groups killing no curves with self-intersection number at most k.     

Preparation of remarkably tough polyHIPE materials via polymerization of oil‐in‐water HIPEs involving 1‐vinyl‐5‐aminotetrazole

Interconnected microcellular polymeric monoliths having unexpected high mechanical strength have been prepared using the high internal phase emulsion (HIPE) methodology. Oil‐in water concentrated emulsions of aqueous 1‐vinyl‐5‐amino [1,2,3,4]tetrazole (1‐VAT) mixed with a low molar ratio (7%) of N,N′‐methylenebisacrylamide as crosslinking agent were prepared using dodecane as dispersed phase and a mixture of hydrophilic surfactants. “Reverse” polyHIPE materials were obtained after radical copolymerization, solvent extraction, and drying. Their morphology, chemical composition, and physicochemical behavior are discussed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2942–2947, 2010