A study of inclusive vector meson production

Data are presented on the reactions π⁺n → ?⁰+X and $\text{K}{}^{\mathrm{?}}\text{p}\text{→}\text{K}{}^1\text{0}\text{(890)+}\text{X}\text{at 6.0}\text{and}\text{7.3}\text{GeV}\text{/c}$, respectively. Comparisons are made with related reactions at higher energies.     

Negative ion mass spectra of highly fluorinated compounds

The negative ion mass spectra of highly fluorinated molecules with varying functionality are discussed. Attempts to obtain negative molecular ions where no positive molecular ion was observed met with little success. An interesting structural correlation for fluorinated ethers was developed based upon the observation of the abundant perfluoro alkoxide anions, CF₃O^? and CF₃(CF₂)₂O^?, in the negative ion mass spectrum.     

Non-ionic polythiophenes: a non-aggregating folded structure in water

The non-aggregating nature of a water-soluble pi-conjugated polythiophene has been characterised by concentration independent thermal denaturing.     

Half-chair conformations of unsaturated heterocyclic compounds

The vicinal proton coupling constants were obtained for some 6-membered ring unsaturated heterocyclic compounds. The R values and ring dihedral angles were determined and found to be consistent with half-chair conformations. Relative to saturated heterocyclic compounds, the effect of the sulfur atom on ring puckering was attenuated. However, an increase in ring puckering resulted from the sulfone group and was attributed to torsional energy.     

Analysis of the 19F and 1H NMR spectra of a number of polyfluoroindenes

¹⁹F and ¹H NMR spectra of the products of nucleophilic attack on octafluoroindene are analysed and structures assigned. The major product in the reaction of butyllithium with octafluoroindene is 3-methylheptafluoroindene, with sodium borohydride it is 2-hydroheptafluoroindene and with sodium methoxide it is 3-methoxyheptafluoroindene. Vacuum pyrolysis of undecafluorotricyclo[5.2.2.0^2,6]undeca- 2,5,8-triene, with elimination of C₂F₄, gives 6-hydroheptafluoroindene as the major product. The NMR assignments are based on the unambiguous synthesis via vacuum pyrolysis of 5,6-dihydrohexafluoroindene, 3-hydro- and 3-methyl-heptafluoroindene and the large long-range coupling of 15 Hz assigned to the F-2, F-6 interaction.     

A limit on the lepton-family number violating process π → μe

A FNAL E799 Collaboration has carried out a search for the lepton-family number violating decay π⁰ → μ^±e using π⁰'s produced from K_L → π⁰π⁰π⁰ decays in flight. No events were observed. Assuming that lepton-family number violation is charge independent, the 90% confidence level upper limit on

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was determined to be 8.6 × 10⁻⁹.     

OH-stretch vibrational spectroscopy of hydroxymethyl hydroperoxide

We report measurement and analysis of the photodissociation spectrum of hydroxymethyl hydroperoxide (HOCH(2)OOH) and its partially deuterated analogue, HOCD(2)OOH, in the OH-stretching region. Spectra are obtained by Fourier transform infrared spectroscopy in the 1nu(OH) and 2nu(OH) regions, and by laser induced fluorescence detection of the OH fragment produced from dissociation of HOCH(2)OOH initiated by excitation of the 4nu(OH) and 5nu(OH) overtone regions (action spectroscopy). A one-dimensional local-mode model of each OH chromophore is used with ab initio calculated OH-stretching potential energy and dipole moment curves at the coupled-cluster level of theory. Major features in the observed absorption and photodissociation spectra are explained by our local-mode model. In the 4nu(OH) region, explanation of the photodissocation spectrum requires a nonuniform quantum yield, which is estimated by assuming statistical energy distribution in the excited state. Based on the estimated dissociation threshold, overtone photodissociation is not expected to significantly influence the atmospheric lifetime of hydroxymethyl hydroperoxide.     

A comparison of the dynamic mechanical relaxation behavior of linear low- and high-density polyethylenes

The mechanical relaxation behaviors of oriented samples of a linear low-density polyethylene (LLDPE) and a high-density polyethylene (HDPE) were studied using tensile dynamic mechanical measurements. The anisotropy and activation energies of the relaxations were determined for several different samples to investigate why the α-relaxation in HDPE has characteristics similar in some respects to both the α- and β-relaxations in LLDPE. It is concluded that the anisotropy of the α-relaxation in LLDPE is determined by c-shear, whereas in HDPE it relates to interlamellar shear. The activation energy measurements, however, show that the thermally activated process for the α-relaxation in both the LLDPE and HDPE is c-shear. It is proposed that, in HDPE, c-shear has to occur before there is enough mobility at the fold surface for interlamellar shear. It is concluded that the β-relaxation is not observed in HDPE because the interlamellar regions are too constrained to allow interlamellar shear without c-shear.