Contribution of the triangle graphs to the neutron electric dipole moment

In the Kobayashi-Maskawa model we compute a new contribution to the neutron electric dipole moment induced byCP violating flavour-changing transitions of the typess→d+gluon+γ through heavy quark loops. This contribution, essentially given by the triangle anomaly graph, is by itself gauge invariant. We obtain from this mechanismD _n /e=3.10^?32 cm, one order of magnitude below our previous estimate from usual penguin diagram contributions.     

The infrared spectrum of californium-249

The Cf-249 spectrum between 3700 and 12,000 cm^?1 has been recorded. The strongest 90 lines are listed.     

Diffusion approximations for the scattering of resonance-line photons: Interior and boundary layer solutions

Resonance-line scattering in static low density media with large optical thickness has a diffusive behavior in both space and frequency because photons belonging to the Lorentzian wings of the line may be scattered almost monochromatically a very large number of times. This diffusive behavior holds on frequency scales and spatial scales, χ_c and τ_c, much larger than the scales associated with one elementary scattering of a wing-photon.A method developed for diffusion approximations in neutron transport theory, suitably generalized to handle diffusion in frequency space, is applied to the case of conservative scattering in a bounded medium with interior sources and zero incoming radiation. The method is to separate the line radiation field into an interior part and a boundary layer part which goes to zero in the interior. Each part is expanded in terms of a small parameter ?, which is the ratio of the mean free-path at frequency χ_c to the characteristic spatial scale τ_c.It is shown that the leading term in the interior asymptotic expansion is isotropic, zero on the boundary, and obeys a space and frequency diffusion equation. In the boundary-layer expansion, the leading term is of order ? and is a solution to a monochromatic transfer equation in a semi-infinite, plane-parallel medium. The emergent radiation field is shown to be of order ? and proportional to the gradient of the interior solution at the boundary. Its angular dependence, in the case of isotropic scattering in the atom frame, is given by the Ambartsoumian H-function. A comparison is presented between numerical solutions of the full transfer equation and asymptotic solutions. Non-conservative scattering and time-dependent problems are briefly discussed.     

Systematic trends in the237neptunium Mössbauer isomer shift: Overlap of IV,V and VI neptunium oxidation states and correlation between isomer shift and crystal structure

The influence of the neptunium ion environment on the²³⁷Np Mössbauer isomer shifts has been studied in various metal coordination complexes: fluorides, oxides, oxide fluorides and polycarboxylates. A linear dependence between the isomer shift and the mean neptunium-ligand distance in a series of hexavalent Np compounds has been evidenced and the feasibility of overlapped isomer shift areas, namely Np(IV), Np(V) and Np(VI) has been established.     

Electronically driven phonon anomalies in transition metal carbides

Large maxima in the generalized susceptibility of χ(q) of TaC calculated from its APW band structure are found to correlate very well with observed soft phonon modes. Such maxima are not found for HfC where phonon anomalies are not observed.     

Room-temperature kinetics of the photoexcited triplet state of acridine in fluorene crystals as obtained from electron spin echo studies

It is shown that electron spin echo results allow an analysis of the complete kinetics of excited triplet spin states at room temperature, not only with respect to all relevant kinetic parameters of the triplet decay and spin relaxation but also the spin selectivity of the triplet population and decay processes.     

NGR study of pyrrhotites obtained in coal hydroliquefaction

Iron Mössbauer spectroscopy has been performed on 38 residues of hydroliquefaction of the French bituminous Freyming coal, without and with added iron based catalysts. 56 to 94 % of the area of each spectrum was occupied by 2, 3, 4 or 5 sextets of Fe_1?xS, either at 295 K or at 78 K or at 4 K. Values of H at 295 K are proposed: 299, 283, 268, 254, 242 and 228 kOe, ±3 kOe, associated with δ(α-Fe)=0.72±0.02 mm/s. The vacancies responsible for the values of H are likely to be randomly distributed. The best accuracy on the relative intensities cannot ensure a precise determination of the overall stoichiometry, so that a better knowledge of the samples is given by the distribution of the Fe sites.