Elastic Scattering of Slow Electrons by Lithium Atoms in the Polarized-Orbital Approximation

1971 ◽  
Vol 49 (12) ◽  
pp. 1670-1679 ◽  
Author(s):  
Bui Tien Dai ◽  
A. D. Stauffer
Keyword(s):  
Cross Section ◽  
Elastic Cross Section ◽  
Wave Functions ◽  
Orbital Method ◽  
Close Coupling ◽  
Hartree Fock ◽  
Resonance Behavior ◽  
Orbital Approximation ◽  
Slow Electrons ◽  
Good Agreement

We have calculated the low energy elastic cross section for electrons incident on lithium atoms via the polarized-orbital method proposed by Temkin. The only further approximations made are the exclusion of core polarization and the use of frozen core Hartree–Fock wave functions. Quite good agreement with previous close-coupling calculations are obtained in the energy range 0.5–3 eV. Surprisingly, the threshold resonance behavior predicted by the close-coupling results is obtained when exchange is neglected, but not when the full polarized-orbital method is used.

Electric Quadrupole Transitions in Na I, Mg II and Al III

1972 ◽  
Vol 50 (11) ◽  
pp. 1169-1174 ◽  
Author(s):  
C. E. Tull ◽  
M. Jackson ◽  
R. P. McEachran ◽  
M. Cohen
Keyword(s):  
Electric Quadrupole ◽  
Wave Functions ◽  
Oscillator Strengths ◽  
Hartree Fock ◽  
Good Agreement

Theoretical multiplet strengths for electric quadrupole transitions between 2S, 2P0, 2D, and 2F0 levels of Na I, Mg II, and Al III have been calculated using Hartree–Fock wave functions of frozen-core type. The resulting 2S–2D oscillator strengths for Na I are in good agreement with calculations by Bogaard and Orr, Boyle and Murray, and Warner; however, for Mg II there is a discrepancy of a factor of 2 between our results and those of Warner.

The elastic scattering of slow electrons by neon and argon

1966 ◽  
Vol 294 (1437) ◽  
pp. 160-174 ◽  
Keyword(s):  
Experimental Data ◽  
Elastic Scattering ◽  
Energy Range ◽  
Orbital Method ◽  
Polarization Effects ◽  
Polarization Contribution ◽  
Slow Electrons ◽  
Good Agreement

The theory of the scattering of electrons by neon and argon in the energy range 0 to 13.6 eV is worked out with allowance for both exchange and polarization effects. The polarized orbital method introduced by Temkin has been used to estimate the polarization contribution and good agreement is obtained with the experimental data, right down to the lowest energies. Inclusion of exchange alone is not sufficient.

Many-Electron Correlations in the Photoionization of a Nitrogen Atom

1974 ◽  
Vol 52 (4) ◽  
pp. 349-354 ◽  
Author(s):  
N. A. Cherepkov ◽  
L. V. Chernysheva ◽  
V. Radojević ◽  
I. Pavlin
Keyword(s):  
Nitrogen Atom ◽  
Cross Section ◽  
Cross Sections ◽  
Random Phase Approximation ◽  
Random Phase ◽  
Electron Correlations ◽  
Sum Rule ◽  
Hartree Fock ◽  
The Cross ◽  
Good Agreement

Photoionization cross sections for the outer shell of the nitrogen atom ground state are calculated in the single-particle Hartree–Fock approximation and, in order to take into account many-electron correlations, also in the Random Phase Approximation with Exchange (RPAE). To be able to apply the RPAE, its modification for the half-filled shell atom, such as nitrogen atom, is presented. Calculation of length and velocity forms of the cross section in both approximations are compared with the available experimental data, and a good agreement is obtained. It has been found that in the RPAE the influence of many-electron correlations in a nitrogen atom is not great, but it is very important since, in contrast to the Hartree–Fock approximation, it results in the validity of the sum rule and the coincidence of the length and velocity forms of the cross sections, in agreement with the requirement of the general theory. The angular distribution of photoelectrons is also calculated in the RPAE, which has not been measured so far.

HARTREE–FOCK WAVE FUNCTIONS FOR EXCITED STATES: III. DIPOLE TRANSITIONS IN THREE-ELECTRON SYSTEMS

1967 ◽  
Vol 45 (5) ◽  
pp. 1661-1673 ◽  
Author(s):  
Maurice Cohen ◽  
Paul S. Kelly
Keyword(s):  
Excited States ◽  
Wave Functions ◽  
Electron Systems ◽  
Matrix Elements ◽  
Isoelectronic Sequence ◽  
Hartree Fock ◽  
Transition Matrix Elements ◽  
Simplified Procedure ◽  
Good Agreement ◽  
Dipole Length

Hartree–Fock wave functions for a number of S, P, and D states of the lithium isoelectronic sequence have been calculated, using a simplified procedure described in an earlier paper. Transition matrix elements for all permitted dipole transitions between these states have been computed using both the dipole length and the dipole velocity formulations. The results are in good agreement with earlier calculations.

HARTREE–FOCK WAVE FUNCTIONS FOR EXCITED STATES: IV. OSCILLATOR STRENGTHS IN THE HELIUM ISOELECTRONIC SEQUENCE

1967 ◽  
Vol 45 (6) ◽  
pp. 2079-2090 ◽  
Author(s):  
Maurice Cohen ◽  
Paul S. Kelly
Keyword(s):  
Matrix Element ◽  
Excited States ◽  
Transition Matrix ◽  
Transition Matrix Element ◽  
Wave Functions ◽  
Oscillator Strengths ◽  
Isoelectronic Sequence ◽  
Hartree Fock ◽  
Good Agreement

Orbital wave functions for a number of singlet and triplet S, P, and D states of the helium sequence through C+4 have been calculated using an approximation described earlier. The wave functions have been employed to calculate the oscillator strengths for all allowed dipole transitions between these states, using both the length and velocity forms of the transition matrix element. Our results are in good agreement with the most accurate values available.

scholarly journals Multiconfiguration Dirac-Hartree-Fock calculations of Landé g-factors for ions of astrophysical interest: B II, C I−IV, Al I−II, Si I−IV, P II, S II, Cl III, Ar IV, Ca I, Ti II, Zr III, and Sn II

2020 ◽  
Vol 639 ◽  
pp. A25 ◽  
Author(s):  
W. Li ◽  
P. Rynkun ◽  
L. Radžiūtė ◽  
G. Gaigalas ◽  
B. Atalay ◽  
...  
Keyword(s):  
General Purpose ◽  
Wave Functions ◽  
Excitation Energies ◽  
Hartree Fock ◽  
Relativistic Configuration ◽  
Experimental Values ◽  
Relativistic Configuration Interaction ◽  
Relative Differences ◽  
Average Uncertainty ◽  
Good Agreement

Aims. The Landé g-factor is an important parameter in astrophysical spectropolarimetry, used to characterize the response of a line to a given value of the magnetic field. The purpose of this paper is to present accurate Landé g-factors for states in B II, C I−IV, Al I−II, Si I−IV, P II, S II, Cl III, Ar IV, Ca I, Ti II, Zr III, and Sn II. Methods. The multiconfiguration Dirac-Hartree-Fock and relativistic configuration interaction methods, which are implemented in the general-purpose relativistic atomic structure package GRASP2K, are employed in the present work to compute the Landé g-factors for states in B II, C I−IV, Al I−II, Si I−IV, P II, S II, Cl III, Ar IV, Ca I, Ti II, Zr III, and Sn II. The accuracy of the wave functions for the states, and thus the accuracy of the resulting Landé g-factors, is evaluated by comparing the computed excitation energies and energy separations with the National Institute of Standards and Technology (NIST) recommended data. Results. All excitation energies are in very good agreement with the NIST values except for Ti II, which has an average difference of 1.06%. The average uncertainty of the energy separations is well below 1% except for the even states of Al I; odd states of Si I, Ca I, Ti II, Zr III; and even states of Sn II for which the relative differences range between 1% and 2%. Comparisons of the computed Landé g-factors are made with available NIST data and experimental values. Analysing the LS-composition of the wave functions, we quantify the departures from LS-coupling and summarize the states for which there is a difference of more than 10% between the computed Landé g-factor and the Landé g-factor in pure LS-coupling. Finally, we compare the computed Landé g-factors with values from the Kurucz database.

Transition Integrals for Si IV and CaII

1962 ◽  
Vol 58 (2) ◽  
pp. 377-381 ◽  
Author(s):  
A. S. Douglas ◽  
R. H. Garstang
Keyword(s):  
Polarization Potential ◽  
Wave Functions ◽  
Mean Square ◽  
Radial Wave ◽  
Atomic Orbitals ◽  
Hartree Fock ◽  
Atomic Wave ◽  
Good Agreement

AbstractAtomic wave functions calculated using the Hartree—Fock equation and a polarization potential are used to obtain mean square radii of atomic orbitals for the ions Si8+ and Ca+, and transition integrals for the Si IV and Ca II spectra. A table of radial wave functions for Ca+ is given. Our results are compared with those obtained from other wave functions, and in one case with an experimental value, and generally good agreement is obtained.

Sign in / Sign up

Export Citation Format

Share Document