ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-18
    Description: The threshold law for ionisation of atoms by positron impact is adduced in analogy with our approach to the electron-atom ionization. It is concluded the Coulomb-dipole region of the potential gives the essential part of the interaction in both cases and leads to the same kind of result: a modulated linear law. An additional process which enters positron ionization is positronium formation in the continuum, but that will not dominate the threshold yield. The result is in sharp contrast to the positron threshold law as recently derived by Klar on the basis of a Wannier-type analysis.
    Keywords: NUCLEAR AND HIGH-ENERGY PHYSICS
    Type: Journal of Physics B - Atomic and Molecular Physics; 15; Apr. 28
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2011-08-17
    Description: Hybrid theory results pertaining to e-N2 scattering have been evaluated for differential elastic and first vibrational excitation cross sections at 5 and 10 eV. Comparison with the recent experiment of Chutjian, Srivastava, and Trajmar is good (1976), although there is an indication that the calculated nonresonant (adiabatic-nuclei) contribution is somewhat too small. A short discussion engendered by this point is given.
    Keywords: NUCLEAR AND HIGH-ENERGY PHYSICS
    Type: Journal of Chemical Physics; 65; Dec. 1
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 2013-08-29
    Description: We report on the first part of a study of electron-hydrogen scattering, using a method which allows for the ab initio calculation of total and elastic cross sections at higher energies. In its general form the method uses complex 'radial' correlation functions, in a (Kohn) T-matrix formalism. The titled method, abbreviated Complex Correlation Kohn T (CCKT) method, is reviewed, in the context of electron-hydrogen scattering, including the derivation of the equation for the (complex) scattering function, and the extraction of the scattering information from the latter. The calculation reported here is restricted to S-waves in the elastic region, where the correlation functions can be taken, without loss of generality, to be real. Phase shifts are calculated using Hylleraas-type correlation functions with up to 95 terms. Results are rigorous lower bounds; they are in general agreement with those of Schwartz, but they are more accurate and outside his error bounds at a couple of energies,
    Keywords: Atomic and Molecular Physics
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2011-08-17
    Description: A distorted-wave program is being developed for calculating the excitation of few-electron ions by electron impact. It uses the exchange approximation to represent the exact initial-state wavefunction in the T-matrix expression for the excitation amplitude. The program has been implemented for excitation of the 2/1,3/(S,P) states of two-electron ions. Some of the astrophysical applications of these cross sections as well as the motivation and requirements of the calculational methodology are discussed.
    Keywords: NUCLEAR AND HIGH-ENERGY PHYSICS
    Type: Journal of Physics B - Atomic and Molecular Physics; 10; Oct. 1
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    facet.materialart.
    Unknown
    In:  Other Sources
    Publication Date: 2011-08-17
    Description: A study is made of the internuclear dependence of the polarizability of N2. Specifically, the dependencies of parallel and perpendicular polarizabilities on internuclear separation is found for the N2 molecule in its ground state. Results are presented for vibrationally elastic cross sections as functions of incident electron energy in an eight-state calculation and for the excitation of the first vibrational state.
    Keywords: NUCLEAR AND HIGH-ENERGY PHYSICS
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2011-08-18
    Description: A polarization potential V(pol) for e-N2 collisions is calculated by the generalization of the static part of the method of polarized orbitals to molecular targets. Partial differential equations (PDE) are derived for polarized orbitals, which are functions of the distance (r) from the molecular center and angle (theta) from the molecular axis. The equations are solved with the use of the noniterative PDE technique. From the polarized orbitals a polarization potential can be constructed whose r and theta dependence is found to be significantly different from the well-known phenomenological one. The two potentials are further compared by carrying out limited hybrid-theory scattering calculations. Only those scattering results based on the calculated V(pol) are in satisfactory accord with experiment.
    Keywords: NUCLEAR AND HIGH-ENERGY PHYSICS
    Type: Physical Review A - General Physics, 3rd Series (ISSN 0556-2791); 28; Aug. 198
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2018-06-06
    Description: Since the original chapter, we briefly review two calculational methods used for basic applications in autoionization of few body systems: (a) complex rotation and (b) a pseudopotential method. Complex rotation, briefly mentioned above, has been extensively applied with great accuracy. Two additional basic systems to be mentioned here are H(sup -) and Ps(sup -) (Ps=positronium). In complex rotation the particle distances are multiplied by the common phase factor given.
    Keywords: Atomic and Molecular Physics
    Format: application/pdf
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2019-07-17
    Description: Calculation of e(-) - H total and elastic partial wave cross sections is being carried out using the complex correlation variational T-matrix method. In this preliminary study, elastic partial wave phase shifts are calculated with the correlation functions which are confined to be real. In that case the method reduces to the conventional optical potential approach with 2 projection operators. The number of terms in the Hylleraas-type wave function for the S-1 phase shifts is 95 while for the S-3 it is 56, except for k = 0.8 where it is 84. Our results, which are rigorous lower bounds, are seen to be in general agreement with those of Schwartz, but they are of greater accuracy and outside of his error limits for k = 0.3 and 0.4 for S-1. The main aim of this approach is the application to higher energy scattering. By virtue of the complex correlation functions, the T-matrix is not unitary so that elastic and total scattering cross sections are independent of each other. Our results will be compared specifically with those of Bray and Stelbovics.
    Keywords: Atomic and Molecular Physics
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2019-07-17
    Description: Two new developments in scattering theory are reported. We show, in a practical way, how one can calculate the full scattering amplitude without invoking a partial wave expansion. First, the integral expression for the scattering amplitude f(theta) is simplified by an analytic integration over the azimuthal angle. Second, the full scattering wavefunction which appears in the integral expression for f(theta) is obtained by solving the Schrodinger equation with the finite element method (FEM). As an example, we calculate electron scattering from the Hartree potential. With minimal computational effort, we obtain accurate and stable results for the scattering amplitude.
    Keywords: Atomic and Molecular Physics
    Type: Atomic Physics; Apr 01, 2001; CT; United States
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2019-07-17
    Description: We propose a novel method to compute in an exact manner the left-hand cut discontinuity of the electron-Atom partial wave scattering amplitude in the complex energy plane within the static stage approximation. Zero energy dispersion relations for electron-Hydrogen scattering are computed numerically for illustration.
    Keywords: Atomic and Molecular Physics
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...