Electronic Structure of the Transition Elements

1973 ◽  
Vol 51 (6) ◽  
pp. 644-647
Author(s):  
K. M. S. Saxena ◽  
S. Fraga
Keyword(s):  
Electronic Structure ◽  
Excited States ◽  
Ground State ◽  
Ground States ◽  
Negative Ions ◽  
State Function ◽  
Transition Elements ◽  
Hartree Fock ◽  
Positive Ions ◽  
Single Set

Numerical Hartree–Fock functions have been determined for the ground states and first excited states of the configurations 3dN4s0 and 3dN4s2 for the negative ions, neutral atoms, and first four positive ions of all the transition elements. The validity of the approximation, embodied in the use of a single set of parameters determined from the ground state function of a configuration for the prediction of the spectroscopic levels arising from it, has been examined in detail in the case of Fe I, 3d64s2, where independent calculations have been carried out for all the excited states.

Fine Structure Intervals in Transition Elements

1975 ◽  
Vol 53 (21) ◽  
pp. 2421-2427 ◽  
Author(s):  
Jacek Karwowski ◽  
K. M. S. Saxena ◽  
Serafin Fraga
Keyword(s):  
Fine Structure ◽  
Ground State ◽  
Orbit Interaction ◽  
Matrix Elements ◽  
Transition Elements ◽  
Hartree Fock ◽  
Positive Ions ◽  
Transition Series ◽  
The Matrix ◽  
New Formulation

A new formulation for the evaluation of the matrix elements of the spin-own orbit interaction in many-electron atoms has been applied to the evaluation of the interaction matrices for pN, dN, and fN configurations, using functions that are simultaneous eigenfunctions of the operators J2, L2,S2, and.Jz; the complete results are available as indicated in the text. Using this formulation, the fine structure intervals for the ground states of the neutral atoms and the first three positive ions of the elements of the three transition series have been calculated within the framework of the monoconfigurational approximation, including the electrostatic and spin-own orbit interaction between the states arising from the configuration under consideration. In each case, the spin–orbit parameter and the set of Slater–Condon integrals, obtained from the numerical Hartree–Fock function for the ground state, were used.

Slater–Condon parameters for the transition elements, evaluated from analytical Hartree–Fock functions

1968 ◽  
Vol 46 (19) ◽  
pp. 2228-2229
Author(s):  
Carolyn Fisk ◽  
Serafin Fraga
Keyword(s):  
Negative Ions ◽  
Neutral Atoms ◽  
Transition Elements ◽  
Hartree Fock ◽  
Positive Ions

The Slater–Condon integrals for the positive ions, neutral atoms, and negative ions from Sc to Zn have been evaluated from analytical Hartree–Fock functions.

Gaussian- and Slater-type bases for ground and certain low-lying excited states of positive and negative ions of the atoms H through Xe based on the generator coordinate Hartree–Fock method

1996 ◽  
Vol 74 (8) ◽  
pp. 1526-1534 ◽  
Author(s):  
A.B.F. da Silva ◽  
M. Trsic
Keyword(s):  
Excited States ◽  
Negative Ions ◽  
Weight Functions ◽  
Slater Type ◽  
Atomic Ions ◽  
Hartree Fock ◽  
Gaussian Type ◽  
Positive Ions ◽  
Generator Coordinate

We applied a discretized version of the generator coordinate Hartree–Fock (GCHF) method to generate Gaussian- and Slater-type functions for mono positive and mono negative ions of the atoms H through Xe. The basis sizes for Slater-type functions are (12s, 10p, 10d) for positive ions, and (13s, 11p, 10d) for negative ions. In the case of Gaussian-type functions the bases are (18s, 12p, 11d) for both positive and negative species. Ground and excited state Hartree–Fock energies are calculated with these bases and the results compared with the best atom-optimized calculations and numerical HF results available. A discussion on the role of weight functions in the evaluation of electronic energies emphasizes the integral character of the GCHF method. Key words: Slater-type bases, Gaussian-type bases, generator coordinate Hartree–Fock, atomic ions.

Hartree–Fock calculation for the electronic structure of H+3 using numerically optimized orbitals

2001 ◽  
Vol 79 (2-3) ◽  
pp. 673-679
Author(s):  
J D Talman
Keyword(s):  
Electronic Structure ◽  
Ground State ◽  
Equilateral Triangle ◽  
Wave Functions ◽  
Equilibrium Geometry ◽  
Molecular Ion ◽  
Interatomic Spacing ◽  
Hartree Fock ◽  
Gaussian Orbitals

The Hartree–Fock wave functions for the ground state of the H2 molecule and the H+3 molecular ion are computed using radial orbitals that are numerically optimized. It is shown that these orbitals yield results comparable in accuracy to those obtained using much larger bases of Gaussian orbitals. As in previous calculations, the equilibrium geometry for H+3 is found to be that of an equilateral triangle, with an interatomic spacing of 1.64a0. PACS No.: 13.15+q

Theoretical Study of the Dissociation and Isomerization of NCS

2003 ◽  
Vol 217 (3) ◽  
pp. 255-264 ◽  
Author(s):  
M. Diehr ◽  
G. Chambaud ◽  
H.-J. Werner
Keyword(s):  
Excited States ◽  
Dissociation Energy ◽  
Ground State ◽  
Spectroscopic Data ◽  
Large Scale ◽  
Theoretical Study ◽  
Ground States ◽  
Electronic Ground State ◽  
Barrier Heights ◽  
Electronic Ground

AbstractLarge scale MRCI calculations have been performed to study the electronic ground state and low-lying excited states of the NCS molecule and its isomers. The isomer CNS is found to be stable and linear. It lies 1.29 eV higher in energy than NCS, while CSN has a much higher energy and is unstable. The dissociation energy of the NCS isomer has been calculated to be 4.25 eV. The isomerization paths between the 2Π ground states of both isomers have been mapped by CASSCF and MRCI calculations. The barriers for the NCS → CNS isomerization in 2A′ and 2A″ symmetry have cyclic forms and the barrier heights have been calculated to be 2.71 eV and 2.44 eV, respectively (MRCI). For both isomers, the collinear dissociation paths to the (diatomic + atom) fragments have been investigated by CASSCF calculations. Spectroscopic data are given for the X2Π ground state and for the A2Σ+ state of CNS. The results are compared with the valence isoelectronic system NCO.

Excited-Atom Production by Electron Bombardment of Alkali-Halides

1986 ◽  
Vol 75 ◽  
Author(s):  
R. E. Walkup ◽  
Ph. Avouris ◽  
A. P. Ghosh
Keyword(s):  
Gas Phase ◽  
Excited States ◽  
Ground State ◽  
Excited Atom ◽  
Alkali Halides ◽  
Electron Bombardment ◽  
Secondary Electrons ◽  
Excited Atoms ◽  
Positive Ions ◽  
Electronically Excited

AbstractWe present experimental results which suggest a new mechanism for the production of excited atoms and ions by electron bombardment of alkali-halides. Doppler shift measurements show that the electronically excited atoms have a thermal velocity distribution in equilibrium with the surface temperature. Measurements of the absolute yield of excited atoms, the distribution of population among the excited states, and the dependence of yield on incident electron current support a model in which excited atoms are produced by gas-phase collisions between desorbed ground-state atoms and secondary electrons. Similarly, gas-phase ionization of ground-state neutrals by secondary electrons accounts for a substantial portion of the positive ions produced by electron bombardment of alkali-halides.

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