Total charge transfer cross-sections for protons colliding with hydrogen atom

Total charge transfer cross-sections for protons impinging on hydrogen has been calculated in Coulomb-projected Börn approximation. It is seen that the present calculation compares well with the available experimental data.     

Neutron-proton transfer reactions leading toT=1 particle-hole states of56Co

Zero range DWBA analysis for two-particle (neutron and proton) transfer reactions is carried out, using simple shell model structure wave functions for⁵⁴Fe,⁵⁶Co and⁵⁸Ni, with⁵⁶Ni inert core. In this structure calculation, a microscopic set of two-body interaction matrix elements derived from the non-local separable potential of Tabakin are employed. These matrix elements include in the perturbation theory two corrections (i) the second-order Börn term and (ii) the appropriate core excitations. Unlike the situation in many two-particle transfer reactions, the fragmentation of the reaction strengths to the excited states with respect to the lowest states of same spin and parity in the above transfer processes is satisfactorily borne out from this analysis.     

Temperature variation of higher-order elastic constants of MgO

An effort has been made for obtaining higher-order elastic constants for MgO starting from basic parameters, viz. nearest-neighbor distance and hardness parameter using Coulomb and Börn-Mayer potentials. These are calculated in a wide temperature range (100–1000 K) and compared with available theoretical and experimental results.     

Der Einfluß eines elektrischen Feldes auf die Absorptionskante von ZnS

In the electric field as has been shown theoretically byFranz andKeldysh there is in crystals an absorption edge shift towards longer wave-lenghts. This effect has been studied and verified on CdS byBöer and co-workers and has led to a more profound understanding of many problems of CdS single crystals conductivity. This paper is a first report on the absorption edge shift of ZnS single crystals in the electric field.     

Inverse spectral problem for delta potentials

The scattering problem for the linear Schrödinger equation on the entire axis has been considered. Conditions under which the knowledge of the discrete spectrum of the Schrödinger operator is sufficient for the reconstruction of the potential have been determined. The main difference from the soliton sector is the self-similarity of the problem under consideration with respect to the extension of the spectral parameter λ. This makes it possible to reduce the inverse scattering problem to the study of the singularity of the Green’s function at λ = 0.     

Classical and quantum properties of a two-sphere singularity

Recently Böhmer and Lobo have shown that a metric due to Florides, which has been used as an interior Schwarzschild solution, can be extended to reveal a classical singularity that has the form of a two-sphere. Here the singularity is shown to be a naked scalar curvature singularity that is both timelike and gravitationally weak. It is also shown to be a quantum singularity because the Klein–Gordon operator associated with quantum mechanical particles approaching the singularity is not essentially self-adjoint.     

On the conformable nonlinear schrödinger equation with second order spatiotemporal and group velocity dispersion coefficients

In this paper, exact traveling wave solutions of the conformable differential equations have been examined. By means of the wave transformation and properties of the conformable derivative (CD), conformable nonlinear Schrödinger equation (CNLSE) has been converted into an integer order differential equation. To extract optical solutions, the wave profile has been divided into amplitude and phase components. A new extension of the Bäcklund method has been offered and applied to the CNLSE which has important applications in quantum mechanics. Some novel exact traveling wave solutions to the CNLSE with group velocity dispersion and second order spatiotemporal dispersion coefficients are successfully obtained by means of this method.     

Die Entwicklung der Durchstrahlungsmethode zur Untersuchung des Wasserhaushaltes von Baumen

Auf grund der Gröβe der Versuchsobjekte bestehen grundsätzliche methodische Schweirigkeiten bei der Beurteilung des Gesamtwasserhaushaltes von Böumen unter ökologischen Bedingungen. Inhalt der vorliegenden Arbeit ist deshalb die Entwicklung einer neuen Methode, die es gestattel, den Wasserhaushalt von Bäumen mit gröβerer Sicherheit zu charakterisieren, als es mit den bisher üblichen Verfahren möglich ist. Die in der Arbeit näher beschribene Grundlage der Methode ist die Dichtebestimmung mit γ-Strahlenden Stamm zur Erfassung der Tagesschwankungen im Wassergehalt des Naumstammes. Das in industriellen Verfahren wietverbreitete Meβprinzip wird hier erstmalig zur Untersuchung des Wasserhaushaltes von bäumen aungewandt. Der Aufbau der Meβanordnungen, die bisher Verwendung fanden, ist ausführlich beschrieben; der weiteren wird als Beispiel ein Versuchsergebnis mitgeteilt. Die Durchstrahlungsmethode hat sich in zahlreichen Untersichungen im VErlaufe von 7 Jahren sehr gut bewährt; eine zusammenfassende Darstellung der bisherigen Ergbnisse wird demnächst in einer bilogischen Fachzeitschrift publiziert werden.     

Inverse scattering method and vector higher order non-linear Schrödinger equation

A generalized inverse scattering method has been developed for arbitrary n-dimensional Lax equations. Subsequently, the method has been used to obtain N-soliton solutions of a vector higher order non-linear Schrödinger equation, proposed by us. It has been shown that under a suitable reduction, the vector higher order non-linear Schrödinger equation reduces to the higher order non-linear Schrödinger equation. An infinite number of conserved quantities have been obtained by solving a set of coupled Riccati equations. Gauge equivalence is shown between the vector higher order non-linear Schrödinger equation and the generalized Landau–Lifshitz equation and the Lax pair for the latter equation has also been constructed in terms of the spin field, establishing direct integrability of the spin system.     

Magnetic Properties of Nanoparticles of Antiferromagnetic Materials

Hyperfine Interactions - The magnetic properties of antiferromagnetic nanoparticles have been studied by Mössbauer spectroscopy and neutron scattering. Temperature series of Mössbauer...     

Mössbauer diffraction in perfect crystals undergoing ultrasonic excitation

The influence of the ultrasonic wave on the dynamic diffraction of the Mössbauer γ quanta in the perfect Si crystals has been studied. Both the scattering intensities and the diffractional Mössbauer spectra for different reflections and ultrasonic frequencesν _s have been measured. Some unusual results such as the enhancement of the elastic scattering at highν _s with ultrasound amplitude growing and non-exponential decrease of the Debye-Waller factor (connected with ultrasonic phonons) at lowν _s have been obtained. The experimental data are in good agreement with the theoretical calculations.     

High pressure experiments with synchrotron radiation

Using a diamond anvil cell (DAC), high pressure ⁵⁷Fe Mössbauer spectroscopy has been performed with the nuclear forward scattering of synchrotron radiation. We used monochromatized synchrotron radiation from an in‐vacuum type undulator as a high‐density strong Mössbauer source with a quite small beam size. Pressure‐induced magnetic hyperfine interactions at ⁵⁷Fe in SrFeO_2.97 has been detected at 74 GPa by a quantum‐beat modulation of the decay rate after collective nuclear excitation with the synchrotron radiation pulse. Evidence for a transition from antiferromagnetism to ferromagnetism of Fe in SrFeO_2.97 at 74 GPa and 300 K has been obtained from the nuclear forward scattering under a transverse magnetic field.     

In-situ identification of iron--zinc intermetallics in galvannealed steel coatings and iron oxides on exposed steel

Identification of all the compounds present in various coatings on steels is particularly difficult. Non-destructive, in-situ analysis is necessary if the fraction of each compound as well as its probable layering within the coating, is to be determined. Mössbauer spectroscopy is one valuable probe capable of uniquely identifying all iron compounds which form as coatings on steel and other iron alloy surfaces. To investigate a complete coating several criteria need to be considered. Removing the coating inevitably leaves a small and perhaps important component intact on the substrate. Therefore investigating the coating as it remains intact on the steel is important if complete identification of the iron compounds is to be made. This also preserves crystalline texture or preferred growth orientation within the coating to which the Mössbauer effect is sensitive. Mössbauer spectroscopy is a non-destructive technique which allows the integrity of the coating to be maintained during analysis. The combined transmission and scattering Mössbauer geometries generally result in accurate analysis of the coating composition. For the scattering geometry added information on compound layering is obtained if separate Mössbauer spectra are recorded using the re-emitted gamma rays as well as the conversion electrons and subsequently emitted X-rays. In-situ scattering Mössbauer spectroscopy has been used to characterize the iron--zinc alloys which form in the coatings of commercially produced corrosion resistant galvannealed sheet steel, a product of great interest to automotive producers. The results show that different amounts of four iron--zinc phases are present depending on the production conditions of the coating. The different phases are also distinctly layered. Mössbauer analyses of corrosion coatings formed on the surface of steels which have been exposed to different environments has also been undertaken. Materials include structural steels exposed for up to 25 years in marine, rural and industrial environments, and the interior surfaces of boiler pipes subjected to adverse chemical and temperature environments.     

The derivative nonlinear Schrödinger equation and the massive Thirring model

The linearization and Bäcklund transformations are obtained for a class of nonlinear partial differential equations, which contains the derivative nonlinear Schrödinger equation and the equations for the massive Thirring model     

Interference of photoelectric and nuclear resonance absorption of 26keVE1 γ-rays in161Dy studied by transmission and scattering Mössbauer experiments

The interference of photoeffect and internal conversion following nuclear resonance absorption of 26 keVE1 γ quanta in¹⁶¹Dy has been measured in Mössbauer transmission experiments and by direct detection of re-emitted conversion electrons in a parallel-plate avalanche counter. The ratio of the amplitudes of the interference terms in transmission and scattering experiments was found to be in agreement with the theory. An angular distribution of the interference effect has been observed in the scattering experiments.     

Mössbauer scattering spectroscopy

The Mössbauer scattering spectra detected by γ-and X-radiation are investigated, and an analytical representation for the scattering integrals is given. It is shown that the use of Mössbauer scattering spectroscopy allows us to determine the interference amplitude, angular correlation function, Debye-Waller factor for Rayleigh scattering, Lamb-Mössbauer factors and linewidths for the source and scatterer, electronic attenuation coefficients of γ-and X-radiation for the scatterer, the total attenuation coefficient of γ-radiation for Rayleigh and Compton scattering, photoabsorption coefficient of γ-radiation in the scatterer and K-shell of⁵⁷Fe, resonance absorption coefficient of Mössbauer radiation, the thickness of the scatterer and the number density of Mössbauer elements in it. An experimental procedure for checking the difference in Lamb-Mössbauer factors for absorption and scattering of Mössbauer radiation is proposed.     

Crystalline Conductance and Absolutely Continuous Spectrum of 1D Samples

We characterize the absolutely continuous spectrum of half-line one-dimensional Schrödinger operators in terms of the limiting behavior of the crystalline Landauer–Büttiker conductance of the associated finite samples.     

Bäcklund transformation for two-dimensional nonlinear evolution equations and the decomposition theorem

The simplest Bäcklund transformations are derived for matrix spectral problems associated with the Dirac equation. Decomposition theorems reducing equations of the nonlinear Schrödinger type to the common action of commuting generalized Toda lattice flows are presented.     

Radiometrische Ermittlung des Chlorgehaltes wäβriger Lösungen

Bekanntlich werden schnelle Neutronen besonders an leichten Atomkernen unter Energieverlust gestreut, ein Vorgang, den man zur Bestimmung des Wasserstoff- oder Wassergehaltes von Materialien wie Böden und Schüttgut benutzt.