Investigating the structure of the Tin M45N45N45 auger spectrum using auger photoelectron coincidence spectroscopy

Auger photoelectron coincidence spectroscopy (APECS) data were collected for the M₄₅N₄₅N₄₅ Auger peak in coincidence with the 3p_3/2, 3d_3/2 and 3d_5/2 photoelectron lines of Tin. Model spectra were created to fit the APECS data from sets of Gaussian curves defined by Parry-Jones et al., J. Phys. C: Solid State Physics, 12 (1979) 1587. These models were then combined using information about the relative intensities of the peaks from the aforementioned paper to produce a model of the Auger peak which proved a good comparison to high resolution AES spectra. The APECS data revealed satelite structure in the M₅N₄₅N₄₅ peak in coincidence with the 3d_5/2 photoelectron line (M₅N₄₅N₄₅:3d_5/2) due to the Mg Kα₃ line of the X-ray source. There was evidence of a small Coster–Kronig component in the M₄N₄₅N₄₅:3d_3/2 data and the M₄₅N₄₅N₄₅:3p_3/2 data showed intensity in the M₄N₄₅N₄₅ and M₅N₄₅N₄₅ regions also arising from Coster–Kronig processes. The contribution of the M₄N₄₅N₄₅ plasmon was included in each of the APECS models and was reflected in the high resolution AES spectra. Slight oxidation of the surface of the sample during each 24-h period produced a 0.7 eV shift of the singles Auger peak to lower kinetic energies. The shift was not reflected in the coincidence peak which produced a spectrum of a clean surface due to the nature of the coincidence experiment.     

Evaluation of 45° method in characterizing the anisotropy of the perpendicular media

The 45° method has become increasingly popular in characterizing the anisotropy energy of perpendicular recording media. However, this method had only been evaluated under the framework of single-domain particle model. In this paper, we evaluate the 45° method using both the Monte-Carlo and LLG simulation by taking into account the grain structure and the inter-granular exchange interactions. The simulations show that multiple domains form during a 45° measurement, even for samples with squareness close to 1. Domain formation becomes less of a problem if a large external field is applied (∼H_k). These modeling results impose question marks on the advantages for the 45° method and suggest that this method should be applied with caution.     

String structures and the index of the Dirac-Ramond operator on orbifolds

We discuss the relationship between string structures and the topological class H ⁴(M,Z) on non-simply connected manifolds. We also investigate to what extent the index formula for the Dirac-Ramond operator detects the class, .Supported by the NSF Grant #84-07109 and by the U.S. Department of Energy (D.O.E.) under contract #DE-AC02-76ER03069On leave from the University of Wroclaw, Wroclaw, Poland     

Distribution of 5S and 45S rDNA sites in plants with holokinetic chromosomes and the "chromosome field" hypothesis

Secondary constrictions or 45S rDNA sites are commonly reported to be located mainly in the terminal regions of the chromosomes. This distribution has been assumed to be related to the existence of a "chromosome field" lying between the centromere and the telomere, an area in which certain cytogenetic events may predominantly occur. If this hypothesis is true this distribution should not be observed in holokinetic chromosomes, as they do not have a localized centromere. In order to evaluate this hypothesis, a comparative study was made of the distributions of 5S and 45S rDNA sites using fluorescence in situ hybridization in representatives of the genera Eleocharis, Diplacrum, Fimbristylis, Kyllinga and Rhynchospora, all of which belong to the family Cyperaceae. The numbers of sites per diploid chromosome complement varied from 2 to ～10 for 5S rDNA, and from 2 to ～45 for 45S rDNA. All of the 11 species analyzed had terminally located 45S rDNA sites on the chromosomes whereas the 5S rDNA sites also generally had terminal distributions, except for the Rhynchospora species, where their position was almost always interstitial. These results, together with other previously published data, suggest that the variation in the number and position of the rDNA sites in species with holokinetic chromosomes is non-random and similar to that reported for species with monocentric chromosomes. Therefore, the predominant terminal position of the 45S rDNA sites does not appear to be influenced by the centromere-telomere polarization as suggested by the "chromosome field" hypothesis. Additionally, the hybridization of 5S and 45S rDNA sites provides interesting markers to distinguish several chromosomes on the rather symmetrical karyotypes of Cyperaceae.     

Generating Relations of the Hypergeometric Functions by the Lie Group-Theoretic Method

In this paper, the generating relations for a set of hypergeometric functions _,,,m (x) are obtained by using the representation of the Lie group SL(2,C) giving a suitable interpretation to the index m in order to derive the elements of Lie algebra. The principle interest in our results lies in the fact that a number of special cases would inevitably yield too many new and known results of the theory of special functions, namely the Laguerre, even and odd generalized Hermite, Meixner, Gottlieb, and Krawtchouk polynomials.     

A note on the global structure of supermoduli spaces

We recall some deformation theory of Susy-curves and study obstructions to projectedness of supermoduli spaces, both from a general standpoint and by means of the local coordinate charts most commonly used in the physical literature. We prove that these give rise to a projected atlas for genusg=2 only.Work partially supported by the National Project Geometria e Fisica, M.P.I.     

Reaction cross sections in the ten-nucleon system

The properties of the 10-nucleon system are investigated with a multiconfiguration resonating-group method, which consists of +⁶Li,d+⁸Be,d+⁸Be^*, and +⁶Li^* cluster configurations, where⁶Li^* and⁸Be^* represent the rotational excited-states of⁶Li and⁸Be with orbital angular momentum equal to 2. The results show that, among reactions initiated from the +⁶Li incident channel, the inelastic-scattering process⁶Li(,)⁶Li^* dominates. The -transfer reactions⁶Li(,d)⁸Be and⁶Li(,d)⁸Be^* have smaller cross sections, but still contribute, on the average, to about one-third of the +⁶Li total reaction cross sections in the centre-of-mass energy region between 12 and 24 MeV. The calculated +⁶Li total reaction cross section at 27 MeV is equal to around 70% of the empirical value obtained by analyzing +⁶Li differential scattering cross-section data. This is a respectable amount, considering the complexity of the problem and that no adjustable parameters are involved in the calculation. Based on the findings of this and previous investigations, some general criteria which govern the importance of cluster-transfer processes in light nuclear systems have also been obtained. These criteria should be very useful in qualitatively understanding the behaviour of other systems that have hitherto not been studied with the multi-configuration resonating-group method.     

Improvement of the Reproducibility and Sensitivity of Laser Microspectral Analysis

The possibility for the concentration sensitivity improvement and the limit of detection of the elements at a laser microspectral analysis is studied by means an absorbtion decrease of the laser emission in the plasma torch.

From the investigations at an incline of 0°, 30°, 45°, 60° on the surface of the sample in the laser emission direction it is established, that the most intensive spectra are obtained at an incline of 45°. At an incline of 45° the intensity of certain spectral lines increases up 3 times in comparison with that of the horizontal surface of the sample. The limit of detection increases with one or two orders. The gradution curves for the determination of Si, Mn, Fe.     

Parametric amplification and harmonic generation in the VUV and XUV

To overcome limitations in the high harmonic conversion efficiency, the possibility of parametric amplification in the VUV and XUV is considered. Potential approaches, including parametric gain transfer from low- to high-order processes, are discussed. Experimentally, a near two photon resonant parametric gain scheme in xenon, excited by femtosecond KrF laser radiation at _p=248 nm, was investigated, leading to signal (_s) and idler (_i) emissions at 149 nm and 760 nm according to 2_p=_s+_i. For the signal field at 149 nm an exponential increase with density and length is obtained. By tuning the excimer laser radiation slightly towards the two-photon resonance, a macroscopic amplification of about 50 at 149 nm was measured. In addition, a sum-mixing signal at 106 nm according to _sum=2_p+_i, showing a similar exponential increase as the 149-nm signal, is observed, which indicates a coupling of both processes with a gain transfer by the common idler field. PACS 42.65.Ky     

Energy parameter and the free-atom behavior of Auger spectra

The L₃M₄₅M₄₅ spectra of V and Cr do not exhibit free atom behavior, in sharp contrast to those of Cu and Zn. An energy difference parameter, Δ ?, derived entirely from observable energies, has been introduced to correlate with the extent of electron localization and free-atom behavior in Auger transitions.     

Propagator,sewing rules,and vacuum amplitude for the Polyakov point particle with ghosts

We apply techniques developed for strings to the case of the spinless point particle. The Polyakov path integral with ghosts is used to obtain the propagator and one-loop vacuum amplitude. The propagator is shown to correspond to the Green's function for the BRST field theory in Siegel gauge. The reparametrization invariance of the Polyakov path integral is shown to lead automatically to the correct trace log result for the one-loop diagram, despite the fact that naive sewing of the ends of a propagator would give an incorrect answer. This type of failure of naive sewing is identical to that found in the string case. The present treatment provides, in the simplified context of the point particle, a pedagogical introduction to Polyakov path integral methods with and without ghosts.     

白光和激光产生的调制不稳定性的比较

在非线性自散焦LiNbO_3∶Fe晶体中,实验观察了用激光作光源和用白光作光源两种情况下所产生的调制不稳定性,并从三个方面对这两种情况进行了比较。实验结果表明:在两种情况下,达到稳定状态前,MI现象都会随辐照时间的增加而变得越来越清晰,并且MI图样都会随着入射光束形状的变化而变化。不同的是,用白光作光源时,灯丝长度方向与晶体c轴方向的夹角大于等于45°时出现MI,而用激光作光源时,入射光束方向与c轴方向的夹角不大于45°才出现MI。     

On the effect of trapped particles in the regime of cyclotron resonance

The motion of particles in a finite amplitude wave, propagating obliquely to the homogeneous magnetostatic field is discussed. As follows from simple integral properties, in the neighbourhood of Doppler-shifted cyclotron resonance similar trapping effects appear as in a plasma without magnetostatic field. Consequences of this trapping are discussed, in particular, the possibility of a strong absorption of the wave, and the origin of stochastic instabilities caused by the perturbation of an effective trapping potential and leading to the acceleration of particles.The author is indebted to Dr. R.Klíma, Dr. J.Lacina and Dr. P.unka for interesting discussions and to Dr. .Körbel, Mrs. P.Jaroová and Mrs. A.Harmáková for numerical calculations.     

A realistic many-body approach to the EMC effect

The EMC effect in few nucleon systems and complex nuclei is calculated within a realistic many-body approach. The effect ofQ ²-rescaling is also investigated.Contributed paper to the symposium Mesons and Light Nuclei IV, Bechyn, Czechoslovakia, September 5–10, 1988.     

Two-proton correlations in the decay of 45Fe

The decay of extremely neutron-deficient 45Fe has been studied in detail by means of a novel type of a gaseous detector employing digital imaging to record tracks of charged particles. The two-proton radioactivity channel was clearly identified. For the first time, the angular and energy correlations between two protons emitted from the nuclear ground state were determined, indicating the genuine three-body character of this decay. The half-life of 45Fe was found to be 2.6+/-0.2 ms and the observed 2p decay branching ratio is 70+/-4%.     

Investigation of the excitation of nitrogen molecules in the positive column of a discharge in a mixture of CO2 and N2

The absolute populations of the electron states of the nitrogen molecule C³_u and B³_g in the positive column of a discharge in a mixture of CO₂ and N₂ at an overall pressure of 2.5 mm Hg, a ratio of the components of 11, and a current of 60 mA, are determined. An estimate is made of the possibility of exciting the electron state C³_u by direct electron collision and by multistage excitation from the electron state B³_g. It is suggested that the most probable process by which the electron state C³_u is excited is multistage excitation from vibrational levels of the electron state B³_g.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 49–52, October, 1972.     

Research on identifying the order of fringe pattern traces using angular scan and zone search method

A method for automatically identifying the order of fringe pattern traces is presented. It uses the simplified Otsu algorithm for obtaining the threshold, the angular scan in the range of 45~ for searching the trace positions, and the zone search technique for identifying different traces. Experimental results show that the proposed method may reliably obtain the order of fringe pattern traces orientating from almost 45° to 90°.     

First evidence for the two-proton decay of 45Fe

Decays of five ⁴⁵Fe atoms have been observed at the fragment separator of GSI. Whereas one event is consistent with the β-decay of ⁴⁵Fe accompanied by the emission of a 10 MeV proton, four decays are consistent with the emission of particle(s) of total energy 1.1±0.1 MeV. This observation represents the first evidence for two-proton ground-state radioactivity, a decay mode predicted for ⁴⁵Fe. The time distribution of the observed decay events corresponds to a half-life of 3.2^+2.6 _-1.0 ms. Received: 17 May 2002 / Accepted: 28 May 2002     

Excitation functions for 44Sc, 46Sc, and 47Sc radionuclides produced in the interaction of 45Sc with deuterons and 6He

Experimental excitation functions are presented for ⁴⁵Sc(d, p)⁴⁶Sc, ⁴⁵Sc(d, t)⁴⁴Sc, ⁴⁵Sc(⁶He, ⁵He*)⁴⁶Sc and ⁴⁵Sc(6He, α)⁴⁷Sc reactions at projectile energies near the Coulomb barrier. The obtained excitation functions for reactions ⁴⁵Sc(d, p)⁴⁶Sc and ⁴⁵Sc(⁶He, ⁵He*)⁴⁶Sc have similar behavior and have a maxima near the Coulomb barriers of these reactions. The compilation of the available experimental data, obtained at deuteron- and ⁶He-energies near the Coulomb barrier, showed that the values of the cross sections at the maxima of the excitation functions obtained in (d, p) reactions and the reactions for one-neutron pickup from the ⁶He projectiles have a different Z-dependence.     

Target-space duality between simple compact Lie groups and Lie algebras under the Hamiltonian formalism: I. Remnants of duality at the classical level

It has been suggested that a possible classical remnant of the phenomenon of target-space duality (T-duality) would be the equivalence of the classical string Hamiltonian systems. Given a simple compact Lie groupG with a bi-invariant metric and a generating function suggested in the physics literature, we follow the above line of thought and work out the canonical transformation generated by together with an Ad-invariant metric and a B-field on the associated Lie algebra ofG so thatG and form a string target-space dual pair at the classical level under the Hamiltonian formalism. In this article, some general features of this Hamiltonian setting are discussed. We study properties of the canonical transformation including a careful analysis of its domain and image. The geometry of the T-dual structure on is lightly touched. We leave the task of tracing back the Hamiltonian formalism at the quantum level to the sequel of this paper.