scholarly journals Relativistic B-Spline R-Matrix Calculations for Electron Scattering from Thallium Atoms

Atoms ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 94
Author(s):  
Yang Wang ◽  
Hai-Liang Du ◽  
Xi-Ming Zhu ◽  
Oleg Zatsarinny ◽  
Klaus Bartschat
Keyword(s):  
Electron Scattering ◽  
Spin Asymmetry ◽  
Electron Collisions ◽  
R Matrix ◽  
B Spline ◽  
Asymmetry Function ◽  
Low Energy Electron ◽  
Impact Energies ◽  
The Impact ◽  
Good Agreement

The Dirac B-spline R-matrix (DBSR) method is employed to treat low-energy electron collisions with thallium atoms. Special emphasis is placed on spin polarization phenomena that are investigated through calculations of the differential cross-section and the spin asymmetry function. Overall, good agreement between the present calculations and the available experimental measurements is found. The contributions of electron exchange to the spin asymmetry cannot be ignored at low impact energies, while the spin–orbit interaction plays an increasingly significant role as the impact energy rises.

scholarly journals Relativistic B-Spline R-Matrix Calculations for Electron Collisions with Ytterbium

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 47
Author(s):  
Kathryn R. Hamilton ◽  
Klaus Bartschat ◽  
Oleg Zatsarinny
Keyword(s):  
Experimental Data ◽  
Electron Scattering ◽  
Cross Sections ◽  
Matrix Method ◽  
Model Potential ◽  
Electron Collisions ◽  
R Matrix ◽  
B Spline ◽  
Potential Approach

We have applied the full-relativistic Dirac B-Spline R-matrix method to obtain cross sections for electron scattering from ytterbium atoms. The results are compared with those obtained from a semi-relativistic (Breit-Pauli) model-potential approach and the few available experimental data.

Numerical Analysis on the Response of Deck Plates Laterally Impacted by a Rectangular Indenter

2018 ◽  
Author(s):  
Ling Zhu ◽  
Junying Gao ◽  
Yinggang Li
Keyword(s):  
Permanent Deformation ◽  
Dynamic Loads ◽  
Parametric Studies ◽  
Ice Floes ◽  
Maximum Impact Force ◽  
Impact Energies ◽  
The Impact ◽  
Deformation Modes ◽  
Theoretical Procedure ◽  
Good Agreement

Ship deck plates are often subjected to localized dynamic loads, such as the loads of landing helicopter or impacts of ice floes. In order to investigate the dynamic response of ship plates subjected to such dynamic loads, a series of numerical simulations are performed on ship plates with different thicknesses. Parametric studies are performed on the impact response of plates, including the thickness of the plates, mass and impact velocity of the rectangular indenter. The maximum permanent deflections of the plates are obtained during the simulation. The relation between maximum force and permanent deflection is obtained and the deformation modes are analyzed. A theoretical procedure is developed to predict the deformation of plates with different initial impact energies, and a good agreement between the theoretical and numerical results is obtained. It has also been observed that the thickness of plates has little effect on the dimensionless maximum permanent deformation and dimensionless maximum impact force.

scholarly journals R-matrix calculation of low-energy electron collisions with LiH

2004 ◽  
Vol 37 (8) ◽  
pp. 1689-1697 ◽  
Author(s):  
B K Antony ◽  
K N Joshipura ◽  
N J Mason ◽  
Jonathan Tennyson
Keyword(s):  
Low Energy ◽  
Energy Electron ◽  
Electron Collisions ◽  
R Matrix ◽  
Low Energy Electron ◽  
Matrix Calculation

scholarly journals Impact force analysis using the B-spline material point method

2021 ◽  
Vol 4 (1) ◽  
pp. 721-729
Author(s):  
Siu Vay Lo ◽  
Nha Thanh Nguyen ◽  
Minh Ngoc Nguyen ◽  
Truong Tich Thien
Keyword(s):  
Contact Force ◽  
Basis Function ◽  
Circular Disk ◽  
Material Point ◽  
B Spline ◽  
Contact Algorithm ◽  
The Impact ◽  
Lagrange Basis ◽  
Derivatives Of ◽  
Good Agreement

In the MPM algorithm, all the particles are formulated in a single-valued velocity field hence the non-slip contact can be satisfied without any contact treatment. However, in some impact and penetration problems, the non-slip contact condition is not appropriate and may even yield unreasonable results, so it is important to overcome this drawback by using a contact algorithm in the MPM. In this paper, the variation of contact force with respect to time caused by the impact is investigated. The MPM using the Lagrange basis function, so causing the cell-crossing phenomenon when a particle moves from one cell to another. The essence of this phenomenon is due to the discontinuity of the gradient of the linear basis function. The accuracy of the results is therefore also affected. The high order B-spline MPM is used in this study to overcome the cell-crossing error. The BSMPM uses higher-order B-spline functions to make sure the derivatives of the shape functions are continuous, so that alleviate the error. The algorithm of MPM and BSMPM has some differences in defining the computational grid. Hence, the original contact algorithm in MPM needs to be modified to be suitable in order to use in the BSMPM. The purpose of this study is to construct a suitable contact algorithm for BSMPM and then use it to investigate the contact force caused by impact. Some numerical examples are presented in this paper, the impact of two circular elastic disks and the impact of a soft circular disk into a stiffer rectangular block. All the results of contact force obtained from this study are compared with finite element results and perform a good agreement, the energy conservation is also considered.

scholarly journals Low-Energy Elastic Electron Scattering from Helium Atoms

Atoms ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 82
Author(s):  
Robert P. McEachran ◽  
Kathryn R. Hamilton ◽  
Klaus Bartschat
Keyword(s):  
Elastic Scattering ◽  
Electron Scattering ◽  
General Purpose ◽  
Orbital Method ◽  
Elastic Electron Scattering ◽  
Close Coupling ◽  
R Matrix ◽  
B Spline ◽  
Helium Atoms ◽  
Atom Collision

We reinvestigate a key process in electron-atom collision physics, the elastic scattering of electrons from helium atoms. Specifically, results from a special-purpose relativistic polarized-orbital method, which is designed to treat elastic scattering only, are compared with those from a very extensive, fully ab initio, general-purpose B-spline R-matrix (close-coupling) code.

scholarly journals Benchmark Angle-Differential Cross-Section Ratios for Excitation of the 4p5s Configuration in Krypton

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 61
Author(s):  
Ahmad Sakaamini ◽  
Jean-Baptiste Faure ◽  
Murtadha A. Khakoo ◽  
Oleg I. Zatsarinny ◽  
Klaus Bartschat
Keyword(s):  
Experimental Data ◽  
Differential Cross Section ◽  
Cross Section ◽  
Electron Scattering ◽  
Spin Exchange ◽  
Electronic Excitations ◽  
Close Coupling ◽  
R Matrix ◽  
B Spline

Benchmark intensity ratio measurements of the energy loss lines of krypton for excitation of the 4p61S0→4p55s[3/2]2, 4p55s[3/2]1, 4p55s′[1/2]0, and 4p55s′[1/2]1 transitions are reported, these being the lowest electronic excitations for krypton. The importance of these ratios as stringent tests of theoretical electron scattering models for the noble gases is discussed, as well as the role of spin-exchange and direct processes regarding the angular dependence of these ratios. The experimental data are compared with predictions from fully-relativistic B-spline R-matrix (close-coupling) calculations.

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