scholarly journals Rotational and Vibrational Transitions in Molecular Collisions

1982 ◽  
Vol 35 (5) ◽  
pp. 593 ◽  
Author(s):  
J Peter Toennies
Keyword(s):  
Cross Sections ◽  
Optical Model ◽  
Vibrational Excitation ◽  
Single Mode ◽  
Quantitative Agreement ◽  
Model Potential ◽  
Ion Collisions ◽  
Forced Oscillator ◽  
Mode Excitation ◽  
Collision Processes

Recent progress in understanding collision processes involving rotational and vibrational excitation in collisions of atoms (ions) with molecules in terms of simple models is illustrated for two systems. Rotational excitation of N2 in collision with He at 27 meV can be explained by an optical model. A more quantitative agreement is achieved by cross sections calculated exactly for the model potential of Tang and Toennies. Vibrational excitation probabilities for resolved single mode excitation of CF4 in small angle 10 eV ion collisions follow a Poisson distribution indicating a breathing sphere forced oscillator behaviour

Systematic nonlocal optical model potential for nucleons

2015 ◽  
Vol 24 (01) ◽  
pp. 1550006 ◽  
Author(s):  
Yuan Tian ◽  
Dan-Yang Pang ◽  
Zhong-Yu Ma
Keyword(s):  
Cross Sections ◽  
Optical Model ◽  
Model Potential ◽  
Nucl Phys ◽  
Angular Distributions ◽  
Model Calculations ◽  
Analyzing Powers ◽  
Optical Model Potential ◽  
Fitting Procedures ◽  
Scattering Cross Sections

Based on the Perey–Buck nonlocal optical model potential, F. Perey and B. Buck, Nucl. Phys. 32 (1962) 353, we obtain a new set of nonlocal optical model potential (NLOMP) parameters for proton and neutron scattering off nuclei. The experimental angular distributions of nucleon scattering off nuclei ranging from 27 Al to 208 Pb with incident energies around 10 MeV to 30 MeV are adopted in the fitting procedures. This NLOMP is energy independent. The chi-squares χ2 obtained in the fittings are comparable to those from the KD03 phenomenological local optical model potentials (OMP) A. Koning and J. Delaroche, Nucl. Phys. A 713 (2003) 231. Good agreement is found in comparisons between optical model calculations using this NLOMP and KD03 in their reproduction to the experimental angular distributions of elastic scattering cross-sections and analyzing powers.

Evaluation of Optical Model Potential Using Neutron Induced Cross Section Reaction for Spherical Uranium-238 Isotope up to 20MeV

2015 ◽  
Vol 59 ◽  
pp. 26-34
Author(s):  
Iman Tarik Al-Alawy ◽  
Ronak Ikram Ali
Keyword(s):  
Experimental Data ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Optical Model ◽  
Threshold Energy ◽  
Model Potential ◽  
Model Parameters ◽  
Incident Neutron ◽  
Optical Model Potential

The evaluation are based on mainly on the calculations of the nuclear optical model potential and relevant parameters are collected and selected from References Input Parameter Library (RIPL) which is being developed under the international project coordinated by the International Atomic Energy Agency (IAEA). The analyzing of a complete energy range has done starting from threshold energy for each reaction. The cross sections are reproduced in fine steps of incident neutron energy with 0.01MeV intervals with their corresponding errors. The recommended cross sections for available experimental data taken from EXFOR library have been calculated for all the considered neutron induced reactions for U-238 isotopes. The calculated results are analyzed and compared with the experimental data. The optimized optical potential model parameters give a very good agreement with the experimental data over the energy range 0.001-20MeV for neutron induced cross section reactions (n,f), (n,tot), (n,el), (n,inl), (n,2n), (n,3n), and (n,γ) for spherical U-238 target elements.

Applicability of the systematic helium-3 potential for triton-nucleus reactions

2015 ◽  
Vol 24 (01) ◽  
pp. 1550005 ◽  
Author(s):  
Yong-Li Xu ◽  
Hai-Rui Guo ◽  
Yin-Lu Han ◽  
Qing-Biao Shen
Keyword(s):  
Elastic Scattering ◽  
Cross Sections ◽  
Optical Model ◽  
Model Potential ◽  
Reaction Cross ◽  
Angular Distributions ◽  
Optical Model Potential ◽  
Helium 3 ◽  
Reasonable Description ◽  
Potential Parameters

The elastic scattering angular distributions of triton are calculated by the obtained systematic helium-3 global optical model potential parameters and compared with the available experimental data. These results show that the present global optical model potential can give a reasonable description of the elastic scattering of triton. The total reaction cross-sections of triton as a function of energy per nucleon are also further investigated and the reasonable results are presented.

scholarly journals Optical Model Potential Using CINDA Library for Neutron Induced Cross Section Reactions for Spherical Uranium-235,238 Isotopes

2015 ◽  
Vol 60 ◽  
pp. 66-73
Author(s):  
Iman Tarik Al-Alawy ◽  
Ronak Ikram Ali
Keyword(s):  
Experimental Data ◽  
Energy Range ◽  
Cross Section ◽  
Cross Sections ◽  
Optical Model ◽  
Threshold Energy ◽  
Model Potential ◽  
Model Parameters ◽  
Incident Neutron ◽  
Optical Model Potential

The calculation are based mainly on the nuclear optical model potential and relevant parameters are collected and selected from References Input Parameter Library (RIPL) which is being developed under the international project coordinated by the International Atomic Energy Agency (IAEA). The analyzing of a complete energy range has done starting from threshold energy for each reaction. The cross sections are reproduced in fine steps of incident neutron energy with 0.01MeV intervals with their corresponding errors. The recommended cross sections for available experimental data taken from CINDA library have been calculated for all the considered neutron induced reactions for spherical U-235 and U-238 isotopes. The calculated results are analyzed and compared with the experimental data. The optimized optical potential model parameters give a very good agreement with the experimental data over the energy range 0.001-20MeV for neutron induced cross section reactions (n,f), (n,tot), (n,el), (n,inl), (n,2n), (n,3n), and (n,γ) for spherical U-235 and U-238 target elements.

scholarly journals NIFS Atomic and Molecular Numerical Database for Collision Processes

Atoms ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 71 ◽  
Author(s):  
Izumi Murakami ◽  
Masatoshi Kato ◽  
Masahiko Emoto ◽  
Daiji Kato ◽  
Hiroyuki A. Sakaue ◽  
...  
Keyword(s):  
Cross Sections ◽  
Numerical Data ◽  
Data Sources ◽  
Rate Coefficients ◽  
Electron Collision ◽  
Fusion Plasma ◽  
Scattering Coefficients ◽  
Bibliographic Information ◽  
Ion Collisions ◽  
Collision Processes

The National Institute for Fusion Science (NIFS) has compiled and developed atomic and molecular numerical databases for various collision processes and makes it accessible from the internet to the public. The database contains numerical data of cross sections and rate coefficients for electron collision or ion collisions with atoms and molecules, attached with bibliographic information on their data sources. The database system provides query forms to search data, and numerical data are retrievable. The graphical output is helpful to understand energy dependence of cross sections and temperature dependence of rate coefficients obtained by various studies. All data are compiled mainly from published literature, and data sources can be tracked by the bibliographic information. We also have data of sputtering yields and back-scattering coefficients for solid surfaces collided by ions in the database. All data in the database are applicable to understand atomic and molecular processes in various plasmas, such as fusion plasma, astrophysical plasma and applied plasma, as well as for understanding plasma–surface interaction in plasmas.

Abrasion cross sections for 20Ne projectiles at 2.1 GeV/nucleon

1983 ◽  
Vol 61 (1) ◽  
pp. 93-98 ◽  
Author(s):  
L. W. Townsend
Keyword(s):  
Cross Sections ◽  
Optical Model ◽  
Particle Density ◽  
Pauli Exclusion Principle ◽  
Model Potential ◽  
Exclusion Principle ◽  
Potential Approximation ◽  
Single Particle Density ◽  
Particle Density Distribution ◽  
Optical Model Potential

Utilizing eikonal scattering theory, an optical model potential approximation to the exact nucleus–nucleus multiple scattering series is used in an abrasion–ablation collision formalism to predict abrasion cross sections for relativistic 20Ne projectile nuclei. Excellent agreement with recent experimental abrasion results is obtained. The sensitivity of the abrasion predictions to Pauli exclusion principle correlation effects and to the assumed shape of the nuclear single-particle density distribution is also demonstrated.

A simplified optical model description of heavy ion fragmentation

1985 ◽  
Vol 63 (2) ◽  
pp. 135-138 ◽  
Author(s):  
L. W. Townsend ◽  
J. W. Wilson ◽  
J. W. Norbury
Keyword(s):  
Cross Sections ◽  
Optical Model ◽  
Production Cross ◽  
Heavy Ion ◽  
Model Potential ◽  
Model Description ◽  
Fragmentation Model ◽  
Mechanical Formalism ◽  
Optical Model Potential ◽  
Quantum Mechanical Formalism

The fragmentation of 213 MeV/nucleon 40Ar ions by 12C targets is described within the context of a simple abrasion–ablation fragmentation model. The abrasion part of the theory utilizes a quantum-mechanical formalism based upon an optical model potential approximation to the exact nucleus-nucleus multiple-scattering series. The ablation stage of the fragmentation is treated as a compound nucleus evaporation. The decay probabilities for the various particle emission channels are computed using the EVAP-4 Monte Carlo computer program. Predictions for production cross sections for isotopes of sulfur, phosphorus, silicon, and aluminum are made and compared with experimental data. The model is also used to compare predicted and experimental element production cross sections for 1.88 GeV/nucleon 56Fe colliding with 12C and 208Pb targets.

Elastic scattering of nucleon by the lightest mirror nuclei 3H and 3He using the optical model potential

2020 ◽  
Vol 29 (09) ◽  
pp. 2050078
Author(s):  
Mohammad F. Alshudifat ◽  
M. Serhan ◽  
M. Abusini
Keyword(s):  
Elastic Scattering ◽  
Cross Sections ◽  
Optical Potential ◽  
Optical Model ◽  
Model Potential ◽  
Angular Distributions ◽  
Spin Orbit ◽  
Individual Volume ◽  
Optical Model Potential ◽  
Potential Parameters

The angular distribution of the nucleon elastic scattering on the lightest mirror nuclei 3H and 3He at incident energies of 6 and 9[Formula: see text]MeV has been analyzed. A new set of phenomenological optical potential parameters has been obtained. A comparison of differential cross-sections has been performed for both elastic scatterings of neutron and proton on the mirror nuclei. The contribution of individual volume, surface, and spin-orbit terms in the optical model potential for the projectiles at different energies was studied. The predicted elastic angular distributions results compared well with the experimental data.

Global optical model potential for alpha projectile

2015 ◽  
Vol 24 (12) ◽  
pp. 1550092 ◽  
Author(s):  
Xin-Wu Su ◽  
Yin-Lu Han
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Cross Sections ◽  
Optical Model ◽  
Mass Range ◽  
Model Potential ◽  
Reaction Cross ◽  
Angular Distributions ◽  
Optical Model Potential ◽  
Reaction Cross Sections

A new set of global phenomenological optical model potential (OMP) parameters for alpha projectile is obtained by simultaneously fitting the experimental data of reaction cross-sections and elastic scattering angular distributions in the mass range of target nuclei [Formula: see text] at incident energies below 386[Formula: see text]MeV. The total reaction cross-sections and elastic scattering angular distributions are calculated and compared with experimental data for different targets. A satisfactory agreement is presented between them.

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