CIOP   05384
CENTRO DE INVESTIGACIONES OPTICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
A program to view the relationship between atomic energy levels and Slater parameters
Autor/es:
PAGAN CESAR; REYNA ALMANDOS JORGE; RAINERI MÓNICA
Lugar:
Foz de Iguazú
Reunión:
Congreso; Encontro de Física 2011; 2011
Institución organizadora:
Sociedad Brasileña de Física
Resumen:
For a single con¯guration description of an atom, the energy levels can be found as a weighted sum of energy
components representing the electrostatic and relativistic interactions, obtained from the atomic hamiltonian.
These energy parameters are usually referred to as Slater parameters, and represent the average con¯guration
energy Eav, the electrostatic direct Fk and exchange Gk integrals, and spin-orbit parameters ³nl. The same is
valid in a multicon¯gurational approach, where we take into account the presence of the con¯guration interaction
integrals Rk and eigenvectors components obtained from the matrix diagonalization for each total angular
momentum (J) value. One of the most widely used Fortran packages for atomic calculation was developed
by R.D. Cowan, and is composed of four codes: RCN, RCN2, RCG, and RCE. Brie°y, RCN calculates the
single-con¯guration radial wavefunctions, RCN2 calculates two-con¯guration radial integrals, and RCG uses
the previous results to obtain energy levels and weighted oscillator strengths. The RCE code is used is to
adjust the values of the energy parameters in order to produce computed atomic energy levels in the best
possible agreement with experimentally known level values by a least-squares calculation. Levels whose energies
are not known experimentally can be disregarded. The output from these codes are ASCII type ¯les. When
large numbers of levels are involved, these ¯les can becomes very large and di±cult to understand. In order
to produce a user-friendly interface, we developed a computer program to control input data and produce a
graphical output from Cowan's RCE code. This program has two main graphical windows. The ¯rst one shows
the Slater energy parameters and controls to select input and output ¯les, \undo", and controls to specify the
input parameters for Cowan's RCE code. Controls are provided held any parameter ¯xed, or allow groups of
parameters forced to vary in such a way that the ratios of the values within a group remain ¯xed relative to
each other. The second window displays the known experimental and the theoretical level values obtained from
a least-squares calculation. The main feature of this code is to allow a dynamical variation of the levels, and
display them on screen as an energy level diagram, while the user varies the Slater parameters with help of the
mouse { all in real time. The code was written in Visual Basic for the Microsoft Windows operational system.Eav, the electrostatic direct Fk and exchange Gk integrals, and spin-orbit parameters ³nl. The same is
valid in a multicon¯gurational approach, where we take into account the presence of the con¯guration interaction
integrals Rk and eigenvectors components obtained from the matrix diagonalization for each total angular
momentum (J) value. One of the most widely used Fortran packages for atomic calculation was developed
by R.D. Cowan, and is composed of four codes: RCN, RCN2, RCG, and RCE. Brie°y, RCN calculates the
single-con¯guration radial wavefunctions, RCN2 calculates two-con¯guration radial integrals, and RCG uses
the previous results to obtain energy levels and weighted oscillator strengths. The RCE code is used is to
adjust the values of the energy parameters in order to produce computed atomic energy levels in the best
possible agreement with experimentally known level values by a least-squares calculation. Levels whose energies
are not known experimentally can be disregarded. The output from these codes are ASCII type ¯les. When
large numbers of levels are involved, these ¯les can becomes very large and di±cult to understand. In order
to produce a user-friendly interface, we developed a computer program to control input data and produce a
graphical output from Cowan's RCE code. This program has two main graphical windows. The ¯rst one shows
the Slater energy parameters and controls to select input and output ¯les, \undo", and controls to specify the
input parameters for Cowan's RCE code. Controls are provided held any parameter ¯xed, or allow groups of
parameters forced to vary in such a way that the ratios of the values within a group remain ¯xed relative to
each other. The second window displays the known experimental and the theoretical level values obtained from
a least-squares calculation. The main feature of this code is to allow a dynamical variation of the levels, and
display them on screen as an energy level diagram, while the user varies the Slater parameters with help of the
mouse { all in real time. The code was written in Visual Basic for the Microsoft Windows operational system.Rk and eigenvectors components obtained from the matrix diagonalization for each total angular
momentum (J) value. One of the most widely used Fortran packages for atomic calculation was developed
by R.D. Cowan, and is composed of four codes: RCN, RCN2, RCG, and RCE. Brie°y, RCN calculates the
single-con¯guration radial wavefunctions, RCN2 calculates two-con¯guration radial integrals, and RCG uses
the previous results to obtain energy levels and weighted oscillator strengths. The RCE code is used is to
adjust the values of the energy parameters in order to produce computed atomic energy levels in the best
possible agreement with experimentally known level values by a least-squares calculation. Levels whose energies
are not known experimentally can be disregarded. The output from these codes are ASCII type ¯les. When
large numbers of levels are involved, these ¯les can becomes very large and di±cult to understand. In order
to produce a user-friendly interface, we developed a computer program to control input data and produce a
graphical output from Cowan's RCE code. This program has two main graphical windows. The ¯rst one shows
the Slater energy parameters and controls to select input and output ¯les, \undo", and controls to specify the
input parameters for Cowan's RCE code. Controls are provided held any parameter ¯xed, or allow groups of
parameters forced to vary in such a way that the ratios of the values within a group remain ¯xed relative to
each other. The second window displays the known experimental and the theoretical level values obtained from
a least-squares calculation. The main feature of this code is to allow a dynamical variation of the levels, and
display them on screen as an energy level diagram, while the user varies the Slater parameters with help of the
mouse { all in real time. The code was written in Visual Basic for the Microsoft Windows operational system.