The structures of some cycloalkane molecular ions by photodissociation and charge-transfer studies in an ICR-spectrometer

The photodissociation spectra of the molecular ions of some cycloalkanes are compared with those of the corresponding acyclic alkanes and alkenes. It is shown that the molecular ions of cyclohexane and cycloheptane are cyclic whereas the cyclopentane ring opens upon ionisation. This conclusion is supported by a study of the charge-transfer equilibria: C₆D₁₂^± + C₆H₁₂ ? C₆D₁₂ + C₆H₁₂^±, C₅D₁₀^± + C₅H₁₀ ? C₅D₁₀ + C₅H₁₀^±. It is furthermore shown that the maxima in the photodissociation spectra of the molecular ions of saturated hydrocarbons correspond to different dissociation processes.     

Diamino-benzo[1,2-d:4,5-d′]bistriazole (DABT), a new useful 1,4-dibenzyne equivalent

The title compound, when treated with two equivalents of lead tetraacetate, is the synthetic equivalent of 1,4-dibenzyne; bis-cycloadducts are formed with dienes and 1,3-dipoles.     

The formation and molecular structure of acetylcyclopentadienylsodium-tetrahydrofuranate

Acetylcyclopentadienylsodium has been isolated in crystalline form as a THF adduct from a reaction between cyclopentadienylsodium and methyl acetate in THF solution. The product has been characterized by means of a single-crystal X-ray diffraction study. {[C₅H₄CMeO]Na·THF}_n crystallizes in the monoclinic space group P2₁/c with unit cell parameters a 6.698(3), b 16.095(4), c 10.661(3) Å, β 92.93(3)° and D_c 1.17 g cm^?3 for Z = 4. Least-squares refinement led to a final R value of 0.080 based on 661 independent observed reflections. The coordination sphere around each sodium atom consists of the oxygen atoms from two C₅H₄CMeO ligands, the oxygen atom of the THF molecule, and an ion contact pair between the sodium and the five ring carbon atoms of the C₅H₄CMeO ligand.     

Spin-rotation measurements in π−p → K0Λ

The first measurements of spin-rotation in meson-baryon scattering in the resonance region are presented. These measurements, for the reaction π^?p → K⁰Λ, confirm the main predictions of a previous partial-wave analysis. Comments are made on resonant couplings in the reaction π^?p → K⁰Λ.     

Inclusiveπ° production in 360 GeVpp interactions using the european hybrid spectrometer

The intermediate and forward gamma detectors of EHS are used to reconstructπ°'s produced by 360 GeV/cpp interactions in the Rapid Cycling Bubble Chamber (RCBC). Using thepp forwardbackward symmetry, the inclusiveπ° production cross section is obtainedσ _π°=(132±11) mb. The averageπ° multiplicity is determined as a function of the charged particle multiplicity. The (1?x) dependence is given for differentp _T regions.     

A phase space analysis of baroclinic flow

The qualitative dynamics of a baroclinic flow experiment are studied by constructing phase space coordinates from a single time series. As the stress on the flow is increased we observe steady, periodic, quasiperiodic, and chaotic flow. The chaotic attractor we observe near the transition has the appearance of a thickened torus.     

A study of the reaction K−p→Λπ+π− at c.m. energies in the range 1.65 to 1.72 GeV

Results are presented of a study of the reaction K^?p→Λπ⁺π^? in the c.m. energy region of 1.65 to 1.72 GeV. Dalitz plots indicate that the reaction proceeds primarily through the intermediate states Σ^?(1385)π⁺ and Σ^?(1385)π⁺, but the resonance bands intersect inside the kinematic ellipse and a simple quasi-two-body interpretation is not possible. Legendre coefficients are presented for the angular distributions of the Λπ⁺ and Λπ^? sub-systems in the overall c.m. frame. Analogous coefficients as suggested by Deler and Valladas, which describe the angular distribution of the final three-body state are also presented.     

Further consideration of the estimation of spectroscopic trends by a perturbation method using Hellmann pseudopotentials

The use of new values of Hellmann pseudopotential parameters and wave functions is shown to yield much better predictions by the method previously proposed. Corrected results are presented for predictions of ionization potentials and the lowest ¹Σ-¹Σ transitions of alkali metal molecules. New predictions are made for the lowest ¹Π-¹Σ transitions of alkali metal molecules.