Double diffraction dissociation and test of pomeron factorization at the CERN ISR

We report the observation of double diffraction dissociation in the process p + p → (pπ⁺π^?) + X at √s of 45 GeV and momentum transfer in the ?t range 0.15?0.53 GeV² at the CERN ISR. The relative rates for elastic, single and double dissociation reactions measured here are found to agree with the prediction of Pomeron factorization.     

Appearance potential spectroscopy of layer materials

It has been shown that soft X-ray appearance potential spectroscopy (SXAPS) can be used as a probe of the conduction band density of states in several of the layer transition metal dichalcogenides, where the pronounced structure seen for TiS₂ agrees well with X-ray absorption data. In contrast, the complex structure seen in the SXAPS of pyrolytic graphite has previously been interpreted in terms of strong plasmon coupling. However, we find that the SXAP spectrum for vacuum cleaved pyrolytic graphite shows details not readily explicable by such an argument but which agree well with what would be expected on the basis of a conduction band self-convolution model. Further strong support for this interpretation is derived from XPS and SXAPS studies of the isostructural, isoelectronic boron nitride.     

Elastic and inelastic scattering of 17.5 and 40.0 MeV 3He particles from 11B

The ³He scattering cross sections have been measured at 17.5 and 40.0 MeV from the ground state and first four excited levels of ¹¹B. The results are analysed with the SCA assuming ¹¹B to be a symmetric rotator and including the K-band mixing introduced by the Coriolis force. A systematic attempt is made to deduce the hexadecapole moment and the sign of the quadrupole deformation of ¹¹B.     

The cell Reynolds number myth

The commonly accepted linear stability analysis for the forward-time centred-space (FTCS) algorithm applied to the transport equation has led to the concept of a cell Reynolds number restriction on the spatial grid size. This paper shows where the commonly accepted original analysis is in error and presents the correct stability restrictions, which are restrictions on the time step, not the spatial grid size. There is no cell Reynolds number restriction. The results are confirmed by numerical computations for the two-dimensional driven cavity problem.     

Some INDO calculations of the dependence of one-bond phosphorus-phosphorus coupling upon molecular geometry

Some INDO parameterized SCPT calculations of ¹J(P? P) and ¹J(P?P) are reported as a function of geometry. At structures corresponding to the gas-phase equilibrium configuration of diphosphine, all of the substituted diphosphines considered are predicted to have negative values of ¹J(P? P). Both contact and non-contact contributions to ¹J(P? P) are significant, whereas the angular variation of ¹J(P? P) is mainly due to the contact term. The non-contact interactions are dominant in determining the value of ¹J(P?P).     

Nitrogen and carbon NMR of some benzofuroxans

¹⁵N and ¹⁴N NMR spectra show that there is no valence tautomerism involving the nitro group in nitro derivatives of benzofuroxan systems and that the N-oxide function has a fixed position in the furoxan ring. Carbon chemical shifts of molecules with one, two or three furoxan rings attached to a benzene ring reveal additivity of effects which makes possible a complete and unambiguous assignment of the shifts.     

A study of factors affecting the InSb c.w. spin-flip Raman laser

The behaviour of the c.w. spin-flip Raman laser is quantified by comparing its operation in the regimes of pump depletion and spin-saturation using InSb samples of different electron concentrations. The use of such a system for wide range spectroscopic applications, complementary to its narrow linewidth characteristic, is indicated.     

Calculation of some nitrogen nuclear screening constants

Some nitrogen screening constants and their anisotropies are calculated within the CNDO/S level of approximation. Satisfactory agreement is found with available experimental data in most cases. In general the reported results are in closer agreement with experiment than are those found from ab initio calculations. The calculated data for the isoelectronic molecules N₂O and CH₂N₂ would be in better agreement with experiment if the assignments of the two nitrogen nuclei were reversed in both cases. A reasonable correlation is obtained with some observed nitrogen chemical shifts. Contributions arising from electronic transitions are reported for N₂, HCN, CH₃CN, CH₃NC, NO₂⁺ and NO₂^?.     

Nonlinear perturbations of linear accretive operators in Banach spaces

It is shown that a strongly continuous semi-group of nonlinear nonexpansive operators can be constructed as lim _n→∞ ((I+t/nB)⁻¹ (I+t/nB)⁻¹) ⁿ whereA is a linearm-accretive operator,B is a nonlinearm-accretive operator, andB satisfies a boundedness condition relative toA.