Raman scattering from mobile cations in sodium,potassium and silver beta”-aluminas

Raman scattering from vibrations of mobile cations in single crystal Na, K, and Agβ”-aluminas has been measured. The frequency of a band near 33 cm^-1 is believed to correspond to the attempt frequency for sodium conduction. The frequencies calculated from a defect model are in good agreement with the observed spectra.     

Erzeugung polarisierter Elektronenstrahlen durch optisches Pumpen

The valence electrons in sodium vapour were aligned by optical pumping to a polarization between 5% and 15%. An electron beam of 10^?12 A current, 10^?2rad divergency and 1 mm diameter has been obtained by ionisation of the sodium vapour with uv-light. This electron beam was polarized up to 2% as measured by Mott scattering.     

Anomalous behavior of Brillouin light scattering at thermal denaturation of lysozyme

The thermal denaturation of lysozyme heated from 293 to 355 K has been studied using Brillouin light scattering. An anomalous temperature behavior of the velocity and damping of hypersound, which is accompanied by a decrease in the intensity of the Brillouin components in the experiments with the 180° scattering geometry and almost complete their disappearance in the case of the 90° scattering geometry, has been observed at the sol-gel transition in the vicinity of 343 K. Such anomalies in the light scattering spectra are absent for a sodium acetate buffer used to prepare protein solutions. A mechanism describing the behavior of the intensities of the Brillouin components has been proposed.     

Resonance Rayleigh scattering and resonance nonlinear scattering of the palladium(II)–acetazolamide chelate with eosin Y and their analytical application

A simple, rapid, and convenient method based on ion association for the determination of acetazolamide has been developed. Acetazolamide can react with palladium(II) to form cationic chelate at sodium acetate–acetic acid buffer solution, which can further react with eosin Y to form an ion association complex. As a result, the resonance Rayleigh scattering, second-order scattering, and frequency doubling scattering intensities are enhanced. Analytical wavelengths of resonance Rayleigh scattering, second-order scattering, and frequency doubling scattering located at 298, 558, and 338?nm, and the linearity range are 0.014–2.5, 0.034–2.5, and 0.119–2.4?µg?mL^?1 respectively. In addition, the optimum conditions and the effect of coexisting substances are investigated. Besides, the structure of ion association complex, the reaction mechanism and the reasons for the enhancement of scattering are discussed through infrared spectra, absorption spectra, and quantum chemical calculations.     

On the interference between Coulomb and nuclear excitation in the inelastic scattering of Li ions

Angular distributions have been measured for inelastic and elastic scattering of ⁶Li ions on ⁵⁸Ni and ¹²⁰Sn. Strong interference between Coulomb and nuclear excitation in inelastic scattering has been observed.     

Raman scattering from magnons in CoCl2 and FeCl2

One-magnon Raman scattering has been observed in the metamagnets CoCl₂ and FeCl₂. The k = 0 magnon energies are 16 ± 1 cm^-1 at 21 K and 16.4 ± 0.4 cm^-1 at 12 K, respectively and these values are in good agreement with previous AFMR and neutron scattering results. A search for two-magnon scattering in both compounds was unsuccessful, largely because of masking from nearby first-order phonons and a weak temperature dependent broad band at 140 cm^-1 in CoCl₂, which is assigned to two-phonon scattering from acoustic phonons.     

Ionic reorientational motions in aqueous solutions: a depolarized light scattering study of NO3 - and SCN-

Depolarized Rayleigh scattering has been measured in the frequency range 0·2 cm^-1 to 200 cm^-1 using a triple monochromator and Fabry-Perot interferometry for solutions of ammonium, sodium and lithium nitrates, for nitric acid and ammonium and potassium thiocyanate over a range of concentrations and temperatures. From comparisons with scattering from water and alkali halide solutions it is concluded that the narrow central component of the scattering arises predominantly from anion reorientational motions. From intensity measurements there is no evidence for significant anion-anion correlations. Infinite dilution relaxation times are discussed in relation to the motions of water molecules in the hydration spheres. Except for very dilute solutions, a simple hydrodynamic model accounts for the temperature and concentration dependence of SCN^- reorientation. For NO₃ ^- it is necessary to assume that the boundary conditions are concentration dependent. In very concentrated nitrate solutions the lineshape is non-lorentzian due, it is argued, to specific cation-anion interactions.     

Elastic scattering of 11B from 209Bi in the energy range 49.8 ⩽ E ⩽ 84.1 MeV

The elastic scattering of ¹¹B from ²⁰⁹Bi has been measured at laboratory energies of 49.8, 51.3, 52.2, 52.8, 54.3, 55.8, 59.8, 64.8, 69.8, 74.8 and 84.1 MeV. These data have been analyzed using a microscopic optical model and the energy dependence of the real and the imaginary parts of the optical potential at near barrier energies has been determined. The “threshold anomaly” observed in the real part of the potential is found to be consistent with the dispersion relation which connects the real and the imaginary parts of the potential. Inelastic scattering and transfer reactions have also been measured at energies of 51.3, 55.8, 59.8 and 74.8 MeV. DWBA calculations for the 3⁻ state in ²⁰⁹Bi are made. From the measured transfer probabilities, using a semiclassical approach the strength of the form factors have been obtained. The fusion cross sections have been derived at these energies from the corresponding quasi-elastic scattering angular distribution data. The fusion cross sections calculated using the energy dependent barriers extracted from the energy dependent real parts of the potential compare well with, that determined from quasi-elastic scattering data and are also in good agreement with simplified coupled channels calculation for fusion incorporating important inelastic and transfer channels.     

Scattering of an atomic beam by a short light pulse

The observation of the scattering of sodium atoms by a short light pulse (≈ 10^?8 s) is treated. The pulse has the spatial structure of a standing wave. The particles are scattered at the expense of the forces of the stimulated light pressure (gradient forces). In a resonance field of the order of 10³ V/cm, the scattering angle is of the order of 0.01 rad.     

Structure of aluminum alloys irradiated with reactor neutrons

Samples of the CAB-1 alloy in the initial state and irradiated with fast neutrons at an fluence of 2 × 10²¹ neutrons/cm² have been studied by small-angle neutron scattering. It has been demonstrated that the observed large scattering cross sections are associated with the presence of nanosized pores with radii R ∼ 5–50 nm in the alloy, whereas for possible inclusions of the Mg₂Si and Si phases, the contrast factors and limiting volume fractions lead to the estimated cross sections that are two orders of magnitude smaller than those observed in the experiment. As a result of the irradiation, the volume fraction of scattering objects (pores) 40–50 nm in radius decreases by a factor of more than two. This is compensated, to a large extent, by an increase in the total fraction of particles with radii of 5–8 and 20–25 nm as the total surface area of the scattering objects increases by 40%.     

Search for states using the knock-out reaction at 600 MeV/c

The knock-out reaction has been used to search for narrow states. The experiment was performed using the 600 MeV/c antiproton beam at LEAR and the high-resolution and large-acceptance magnetic spectrometer SPES II. The A-dependence of the annihilation-induced proton spectra has been studied on ²H, ⁶Li, ¹²C, ⁶³Cu, ²⁰⁸Pb and ²⁰⁹Bi. The quasi-free elastic scattering observed in the lighter targets, and the comparison with the free scattering, also observed in this experiment, determine an effective proton number N_eff for 1s- and 1p-shell protons. No evidence for narrow bound or resonant states could be found. Upper limits for their production are one order of magnitude lower than certain theoretical predictions, but consistent with the properties of the interaction, as established from recent elastic and inelastic scattering as well as from studies of antiprotonic atoms.     

Alpha-transfer processes in heavy-ion scattering

In the differential cross sections for the elastic scattering between an α-conjugate target and projectile, a rising oscillatory structure is often observed in the backward-angle region. An α-transfer mechanism is proposed to explain this anomalous phenomenon. A nuclear molecularorbit approximation theory for both 1α- and 2α-transfer processes has been formulated and applied to ¹⁶O + ²⁰Ne and ¹²C + ²⁰Ne scattering systems with different projectile energies. The experimental rising structures shown in these scatterings are well reproduced with parameters fairly consistent with spectroscopic data. An independent-α-particle model wave function has been used for the evaluation of the exchange potential, which gives better agreement with experiment than the Buttle-Goldfarb approximation can usually provide.     

Second order resonance Raman scattering in As2S3 glass

First and second order resonance enhanced Raman scattering has been observed for As₂S₃ glass. First order scattering is dominated by a peak at 340 cm^-1 due to the symmetric stretch of the AsS₃ pyramidal group. Two partially resolved second order peaks are observed at about 630 and 710 cm^-1 whose relative intensities are highly temperature dependent and which are due respectively to overtones of the antisymmetric and symmetric AsS₃ stretching modes.     

Dynamical effects of the repulsive core in 54.7 MeV 16O + 28Si large-angle elastic scattering

The inclusion of a short-range repulsive term in the real part of the optical potential has previously been shown to be needed to explain the 54.7 MeV ¹⁶O + ²⁸Si large-angle scattering data. The dynamical effects arising from this repulsive core are studied here. The changes in the angular distribution for this system brought about by the presence of the core are shown to be due to an increased reflectivity in the low-angular-momentum partial waves affecting mostly the nearside component of the scattering amplitude. From this study we draw inferences about the expected behaviour of the elastic scattering cross section for heavier systems where anomalous large-angle scattering is also observed.     

Giant resonance excitation by 156 MeV6Li scattering

The excitation of the giant quadrupole resonance in ²⁰⁸Pb has been observed by inelastic scattering of 156 MeV ⁶Li ions. The continuum background in the giant resonance region of the measured ⁶Li spectra proves to be strongly reduced as compared to the spectra obtained by inelastic scattering of lighter projectiles, which makes ⁶Li scattering a promising tool for more detailed studies.     

Raman susceptibility measurements and stimulated Raman effect in KDP

The propagation constant of the stimulated Raman process and Raman susceptibility measurements in KDP are reported. The stimulated Raman scattering due to 915 cm^-1 and 93 cm^-1 vibration in KDP has been experimentally observed.     

Comparison of the elastic and inelastic scatterings between152Sm+12C and148 Nd+16O

Angular distributions of elastic and inelastic scattering have been measured for¹⁵²Sm+¹²C at 63.2 MeV and¹⁴⁸Nd+¹⁶O at 90.9 MeV. An evident interference pattern in the inelastic scattering has been observed for the first time in a strong Coulomb coupling system.We are indebted to Dr. S. Pieper for supplying the Ptolemy Program. One of us (Chenglie Jiang) would like to acknowledge the Argonne National Laboratory for the opportunity given, to perform theoretical calculations with the code Ptolemy during his visit there. Thanks are also due to Mr. H. Folger (GSI, Germany) for supplying the targets. This work was supported in part by China National Nature Science Fundation.     

Resonant X-ray scattering from a rotating medium: The Nuclear Lighthouse Effect

A coherently excited nuclear state is carried with a rotating sample so that its radiative decay is redirected by the rotation angle that has developed during its lifetime. As a result, the time spectrum of the nuclear decay is mapped to an angular scale. This effect has been observed in nuclear resonant scattering of synchrotron radiation from a rotating ⁵⁷Fe metal foil. Applications with respect to elastic and inelastic nuclear resonant scattering are discussed. This revised version was published online in August 2006 with corrections to the Cover Date.     

Comparison of sub-coulomb stripping and analog resonance results in Zr

The ⁹²Zr(d, p)⁹³Zr reaction, leading to states in ⁹³Zr which are parents of analog states observed in ⁹²Zr(p, p) elastic scattering, has been studied for incident deuteron energies below the Coulomb barrier. For each of the parent states the reduced normalization has been extracted, and these have been compared with the reduced normalizations calculated for the analog resonances on the basis of various analog resonance theories.