COLLISIONS OF LONG-LIVED EXCITED IONS OF OXYGEN AND NITROGEN

The role of some excited ions in laboratory ion–molecule reactions has been investigated, and their possible importance in the upper atmosphere considered. The mass spectrometer techniques of Aston banding and of comparing I.P. curves of parent and product ions have been applied to studies of collision-induced dissociation and charge exchange of oxygen and nitrogen in their parent gas. In every case studied, cross sections depended markedly upon the presence in the ion beam of ions in metastable or long-lived radiative states. In order that an ion reach the collision region, it had to have a mean lifetime greater than 3 μsec.The a 4Πu and b 4Σg excited states of O2+ were identified in the collision[Formula: see text]Higher states of O2+, which have not as yet been identified spectroscopically, were found in the collision[Formula: see text]The thresholds of these new states are 23.9, 27.9, 31.3, and 34.1 eV with an uncertainty ±0.2 eV. From the collision-induced dissociation of N2+, the A 2Πu and the [Formula: see text] states have been identified. Also, the reported transfer of the ν = 3 level of the B [Formula: see text] to the ν = 14 level of the A 2Πu was found.The cross section for 10/01 charged exchange of N2+ in N2 exhibited a marked decrease as excited-state ions diluted the beam. The 10/01 collisions of N+ in N2 and O+ in O2 exhibited an increase in cross section as metastables were added to the parent ion beam. The 10/20 reaction of O2+ in O2 was also observed to depend on excited O2+ ions.

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Oxygen K near edge structures studied with multiple scattering calculations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100104583 ◽

1988 ◽

Vol 46 ◽

pp. 504-505

Author(s):

Xudong Weng ◽

Peter Rez

Keyword(s):

Cross Section ◽

Cross Sections ◽

Partial Cross Section ◽

Energy Window ◽

Edge Structure ◽

Fine Structures ◽

Hydrogenic Model ◽

Electron Energy Loss ◽

Quantitative Chemical

In electron energy loss spectroscopy, quantitative chemical microanalysis is performed by comparison of the intensity under a specific inner shell edge with the corresponding partial cross section. There are two commonly used models for calculations of atomic partial cross sections, the hydrogenic model and the Hartree-Slater model. Partial cross sections could also be measured from standards of known compositions. These partial cross sections are complicated by variations in the edge shapes, such as the near edge structure (ELNES) and extended fine structures (ELEXFS). The role of these solid state effects in the partial cross sections, and the transferability of the partial cross sections from material to material, has yet to be fully explored. In this work, we consider the oxygen K edge in several oxides as oxygen is present in many materials. Since the energy window of interest is in the range of 20-100 eV, we limit ourselves to the near edge structures.

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An Study of Influence of Imperfections on the Delamination of Diamond-Like Carbon Films

MRS Proceedings ◽

10.1557/proc-719-f8.36 ◽

2002 ◽

Vol 719 ◽

Author(s):

Myoung-Woon Moon ◽

Kyang-Ryel Lee ◽

Jin-Won Chung ◽

Kyu Hwan Oh

Keyword(s):

Cross Sections ◽

Focused Ion Beam ◽

Imaging System ◽

Ion Beam ◽

Carbon Films ◽

Diamond Like Carbon ◽

Glass Substrates ◽

Atomic Force ◽

Initiation And Propagation

AbstractThe role of imperfections on the initiation and propagation of interface delaminations in compressed thin films has been analyzed using experiments with diamond-like carbon (DLC) films deposited onto glass substrates. The surface topologies and interface separations have been characterized by using the Atomic Force Microscope (AFM) and the Focused Ion Beam (FIB) imaging system. The lengths and amplitudes of numerous imperfections have been measured by AFM and the interface separations characterized on cross sections made with the FIB. Chemical analysis of several sites, performed using Auger Electron Spectroscopy (AES), has revealed the origin of the imperfections. The incidence of buckles has been correlated with the imperfection length.

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NONLINEAR ANALYSIS OF STATICALLY INDETERMINATE WOODEN STRUCTURES AND OPTIMIZATION OF CROSS SECTION DIMENSIONS OF DOME RIBS

International Journal for Computational Civil and Structural Engineering ◽

10.22337/2587-9618-2018-14-4-130-139 ◽

2018 ◽

Vol 14 (4) ◽

pp. 130-139 ◽

Cited By ~ 4

Author(s):

Konstantin P. Pyatikrestovsky ◽

Boris S. Sokolov

Keyword(s):

Nonlinear Analysis ◽

Cross Section ◽

Cross Sections ◽

Frame Analysis ◽

Significant Part ◽

Design Recommendations ◽

Longitudinal Ribs ◽

Non Linear ◽

Wooden Structures

The analysis of the behaviour of natural structures of laminated wood domes and the numerous preliminary calculations have shown the possibility of saving materials by reducing the height of cross sections of meridional ribs. This is especially effective when you include in design of skins, performing a role of building shell, the collaboration with frame elements (annular and longitudinal ribs). Multiple static indeterminacy of such structure allows its non-linear work and the redistribution of forces under nonuniform loads. At the same ime, the skin carries a significant part of the forces appearing in the shell and the ribs are underloaded. The tress-strain states of all elements are investigated. For the frame analysis the calculation is performed by the method of integral module that allows controlling strength resistance of a structure at any moment of its operation. The design recommendations for section dimensions of a shell are developed.

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EXTRACTION OF RESONANCE PARAMETERS AND ROLE OF THE FINAL STATE INTERACTIONS

International Journal of Modern Physics Conference Series ◽

10.1142/s2010194514600829 ◽

2014 ◽

Vol 26 ◽

pp. 1460082 ◽

Cited By ~ 1

Author(s):

IGOR I. STRAKOVSKY ◽

WILLIAM J. BRISCOE ◽

ALEXANDER E. KUDRYAVTSEV ◽

VLADIMIR E. TARASOV

Keyword(s):

Cross Section ◽

Cross Sections ◽

Impulse Approximation ◽

Pion Photoproduction ◽

Final State ◽

The World ◽

Final State Interactions ◽

Watson’S Theorem ◽

Photoproduction Data

We present an overview of the SAID group effort to analyze new γn → π-p cross sections vs. the world database to get new multipoles and determine neutron electromagnetic couplings. The differential cross section for the processes γn → π-p was extracted from new measurements at CLAS and MAMI-B accounting for Fermi motion effects in the impulse approximation (IA) as well as NN- and πN-FSI effects beyond the IA. We evaluated results of several pion photoproduction analyses and compared πN PWA results as a constraint for analyses of pion photoproduction data (Watson's theorem).

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Ion Beam Analysis of O, N, and B Compositions in Materials Using Non-Rutherford Scattering of Protons

MRS Proceedings ◽

10.1557/proc-128-375 ◽

1988 ◽

Vol 128 ◽

Author(s):

N. R. Parikh ◽

Z. H. Zhang ◽

M. L. Swanson ◽

N. Yu ◽

W. K. Chu

Keyword(s):

Cross Section ◽

Cross Sections ◽

Ion Beam ◽

Proton Scattering ◽

Light Elements ◽

Ion Scattering ◽

Scattering Cross ◽

Beam Analysis ◽

Rutherford Scattering ◽

Scattering Cross Sections

ABSTRACTElastic scattering of protons with energies from 1.5 MeV to 2 MeV was used to determine the concentration of oxygen in Y-Ba-Cu-O compound, nitrogen in GaN films, and boron in B-Si glass and other materials. Proton scattering from light elements in this energy range exhibits non-Rutherford scattering cross section, which are enhanced by a factor of 3 to 6 or more relative to the Rutherford scattering cross sections. Thus the sensitivity for the light clement detection is considerably larger than that obtained by He ion scattering.Quantitative analysis by proton scattering is discussed and compared with other methods.

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MEASURING CAPTURE CROSS SECTIONS FOR HEAVY-ELEMENT PRODUCTION

International Journal of Modern Physics E ◽

10.1142/s0218301304002077 ◽

2004 ◽

Vol 13 (01) ◽

pp. 293-300

Author(s):

NEIL ROWLEY ◽

NABILA GRAR

Keyword(s):

Cross Section ◽

Compound Nucleus ◽

Cross Sections ◽

Reaction Path ◽

Superheavy Element ◽

Evaporation Residue ◽

Capture Cross ◽

Total Capture ◽

Capture Cross Sections

The creation of the nucleus of a superheavy element follows an extremely complex reaction path starting with the crossing of an external potential barrier (or distribution of barriers). This is followed by the evolution towards an equilibrated compound nucleus, which takes place in competition with pre-compound-nucleus fission (quasi-fission). Once formed the equilibrated compound nucleus must still survive against true fusion to yield a relatively long-lived evaporation residue. Much of this path is poorly understood, though recently, progress has been made on the role of the entrance-channel in quasi-fission. This will be briefly reported and a method proposed to measure the total capture cross section for such systems directly.

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Taming the Energy Rise of the Total Proton-Proton Cross-Section

Universe ◽

10.3390/universe5050106 ◽

2019 ◽

Vol 5 (5) ◽

pp. 106 ◽

Cited By ~ 1

Author(s):

Sergey Ostapchenko ◽

Marcus Bleicher

Keyword(s):

Cross Section ◽

Cross Sections ◽

Strong Increase ◽

Momentum Fraction ◽

Proton Proton ◽

High Energies ◽

Model Predictions ◽

Potential Impact ◽

Very High

Steep rise of parton densities in the limit of small parton momentum fraction x poses a challenge for describing the observed energy-dependence of the total and inelastic proton-proton cross sections σ p p tot / inel : considering a realistic parton spatial distribution, one obtains a too-strong increase of σ p p tot / inel in the limit of very high energies. We discuss various mechanisms which allow one to tame such a rise, paying special attention to the role of parton-parton correlations. In addition, we investigate a potential impact on model predictions for σ p p tot, related to dynamical higher twist corrections to parton-production processes.

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EMPIRICAL FORMALISM FOR PROJECTILE FRAGMENTATION AND PRODUCTION OF NEW NEUTRON-RICH NUCLEI WITH RIBS

Modern Physics Letters A ◽

10.1142/s0217732398002837 ◽

1998 ◽

Vol 13 (33) ◽

pp. 2665-2678 ◽

Cited By ~ 2

Author(s):

DEBASIS BHOWMICK ◽

ALOK CHAKRABARTI ◽

D. N. BASU ◽

PREMOMOY GHOSH ◽

RANJANA GOSWAMI

Keyword(s):

Cross Section ◽

Cross Sections ◽

Ion Beam ◽

Production Cross ◽

High Energy ◽

Exotic Nuclei ◽

Radioactive Beams ◽

Fragment Separator ◽

Projectile Fragment ◽

The Cross

The projectile fragment separator type radioactive ion beam (RIB) facilities, being developed in different laboratories, provide the scope for producing many new exotic nuclei through fragmentation of high energy radioactive ion (RI) beams. A new empirical parametrization for the estimation of cross-sections of projectile fragments has been prescribed for studying the advantages and limitations of high energy RI beams for the production of new exotic nuclei. The parametrization reproduces the experimental data for the production of fragments from neutron-rich projectiles accurately in contrast to the existing parametrization which tends to overestimate the cross-section of neutron-rich fragments in most cases. The modified formalism has been used to compute the cross-sections of neutron-rich species produced by fragmentation of radioactive projectiles (RIBs). It has been found that, given any limit of production cross-section, the exoticity of the fragment increases rather slowly and shows a saturation tendency as the projectile is made more and more exotic. This essentially limits, to an extent, the utility of very neutron-rich radioactive beams vis-a-vis production of new neutron-rich exotic species.

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