Juan Rubiano - Academia.edu (original) (raw)

Papers by Juan Rubiano

Research paper thumbnail of Low Z opacities at high densities

Journal of Quantitative Spectroscopy & Radiative Transfer, 2003

We present an experimental study devoted to measuring the opacity of bound-bound transitions in u... more We present an experimental study devoted to measuring the opacity of bound-bound transitions in ultra-dense, hot, low Z plasmas, which are at the extreme limit for conditions of both emission spectroscopy and absorption spectroscopy. In this work, we develop an absorption spectroscopy experiment specially adapted to high-density diagnostics, using newly designed structured targets and an ultra-high resolution spectrograph. An aluminum plasma is chosen as the ÿrst candidate and the opacity of the He-like 1s 2 -1s2p (Heÿ) and 1s 2 -1s3p (He ) transitions are measured. ?

Research paper thumbnail of A comparison of two atomic models for the radiative properties of dense hot low Z plasmas

Journal of Quantitative Spectroscopy & Radiative Transfer, 2003

In this work, two di erent atomic models (ANALOP based on parametric potentials and IDEFIX based ... more In this work, two di erent atomic models (ANALOP based on parametric potentials and IDEFIX based on the dicenter model) are used to calculate the opacities for bound-bound transitions in hot dense, low Z plasmas, and the results are compared to each other. In addition, the ANALOP code has been used to compute free-bound cross sections for hydrogen-like ions. ?

Research paper thumbnail of Relativistic quantum mechanic calculation of photoionization cross-section of hydrogenic and non-hydrogenic states using analytical potentials

Journal of Quantitative Spectroscopy & Radiative Transfer, 2005

Photoionization process is a subject of special importance in many areas of physics. Numerical me... more Photoionization process is a subject of special importance in many areas of physics. Numerical methods must be used in order to obtain photoionization cross-sections for non-hydrogenic levels. The atomic data required to calculate them is huge so self-consistent calculations increase computing time considerably. Analytical potentials are a useful alternative because they avoid the iterative procedures typical in self-consistent models. In this work, we present a relativistic quantum calculation of photoionization cross-sections for isolated ions based on an analytical potential to obtain the required atomic data, which is valid both for hydrogenic and non-hydrogenic ions. Comparisons between our results and others obtained using either widely used analytical expressions for the cross-sections or more sophisticated calculations are done.

Research paper thumbnail of Influence of the atomic description and configuration interaction effects on collisional-radiative calculations of low ionized carbon plasmas

Journal of Quantitative Spectroscopy & Radiative Transfer, 2009

An analysis of the influence of the atomic description and the configuration interaction effects ... more An analysis of the influence of the atomic description and the configuration interaction effects in the calculation of plasma average ionization and relevant plasma radiative properties such as the spectrally resolved emissivities and opacities, radiative power losses and mean opacities, is performed. Since the larger effects of the configuration interaction are due to the lower ionization stages, i.e. CI and

Research paper thumbnail of A screened hydrogenic model using analytical potentials

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

The screened hydrogenic model and analytical potentials are tools widely used for atomic calculat... more The screened hydrogenic model and analytical potentials are tools widely used for atomic calculation of dense plasma physics. In this paper, we present a simple method to obtain screened hydrogenic energy levels and wave functions from analytical potentials for ions. Atomic data obtained using this model are compared satisfactorily with results of similar models and of more sophisticated self-consistent codes.

Research paper thumbnail of Calculation of the radiative opacity of laser-produced plasmas using a relativistic-screened hydrogenic model

Journal of Quantitative Spectroscopy & Radiative Transfer, 2004

In this work, we use a relativistic-screened hydrogenic model to compute the radiative opacity of... more In this work, we use a relativistic-screened hydrogenic model to compute the radiative opacity of laserproduced plasmas. The model is based on a set of screening charges which allow one to easily calculate atomic properties of isolated ions. These screened charges have been ÿtted to a fourth-order polynomial depending on the nuclear charge Z for ground and single excited states of ions belonging to the isoelectronic sequences comprised between He-like to U-like. In the opacity model used, ionic populations are obtained by solving the Saha equation including degeneracy corrections. Bound-bound transitions are determined using a Voigt proÿle for line shape, which includes natural, collisional, Doppler and UTA widths. Bound-free and free-free opacities are evaluated using the Kramer cross-sections with appropriate corrections. Scattering processes are computed through the use of the Thomson formula with corrections. The results are compared with other screened hydrogenic models and more sophisticated self-consistent codes. ?

Research paper thumbnail of An effective analytical potential including plasma effects

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

In this work, we have developed a method to build an e ective analytical potential for ions in sl... more In this work, we have developed a method to build an e ective analytical potential for ions in slightly nonideal plasmas. This proposed potential is obtained from an analytical isolated potential with one or two parameters depending on the total number of electrons of the ion. The plasma e ects are included by means of the linearized Debye-H uckel approximation taking into account the reaction of the plasma-charge density to the optical electron. Due to the in uence of the plasma over the atomic potential, this permits to obtain level energies and wave functions as a function of the inverse of Debye radius, the quantum numbers, the nuclear charge, the bound electron number and the ionization state of the ion. Also, we compare the analytical e ective potential proposed in this paper with other ones very well known in the available literature. ?

Research paper thumbnail of Development of an analytical potential to include excited configurations

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

Excited conÿgurations are very important in dense plasma physics. In this work we propose a new a... more Excited conÿgurations are very important in dense plasma physics. In this work we propose a new analytical potential for excited conÿgurations obtained from another one for ground conÿguration. With this potential several atomic magnitudes have been calculated for ions in excited conÿgurations analyzing what kind of excited conÿgurations introduce more in uences in those magnitudes. Using this potential, atomic data generated are satisfactorily compared with those obtained using other analytical potential using sophisticated self-consistent codes, and with others available in the bibliography. ?

Research paper thumbnail of ANALYTICAL EXPRESSIONS FOR THE n-ORDER MOMENTA OF CHARGE DISTRIBUTION FOR IONS

Journal of Quantitative Spectroscopy & Radiative Transfer, 1998

In this work a family of four analytic expressions for the n-order momenta of the charge distribu... more In this work a family of four analytic expressions for the n-order momenta of the charge distribution for ions, 〈rn〉, depending on three, two, or one parameters will be presented. These expressions are derived through the use of electronic charge densities obtained from a family of four analytical potentials. The parameters in the expressions were obtained for ions in the

Research paper thumbnail of Calculation of the radiative opacity of laser-produced plasmas using a relativistic-screened hydrogenic model

Journal of Quantitative Spectroscopy & Radiative Transfer, 2004

In this work, we use a relativistic-screened hydrogenic model to compute the radiative opacity of... more In this work, we use a relativistic-screened hydrogenic model to compute the radiative opacity of laserproduced plasmas. The model is based on a set of screening charges which allow one to easily calculate atomic properties of isolated ions. These screened charges have been ÿtted to a fourth-order polynomial depending on the nuclear charge Z for ground and single excited states of ions belonging to the isoelectronic sequences comprised between He-like to U-like. In the opacity model used, ionic populations are obtained by solving the Saha equation including degeneracy corrections. Bound-bound transitions are determined using a Voigt proÿle for line shape, which includes natural, collisional, Doppler and UTA widths. Bound-free and free-free opacities are evaluated using the Kramer cross-sections with appropriate corrections. Scattering processes are computed through the use of the Thomson formula with corrections. The results are compared with other screened hydrogenic models and more sophisticated self-consistent codes. ?

Research paper thumbnail of Development of an analytical potential to include excited configurations

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

Excited conÿgurations are very important in dense plasma physics. In this work we propose a new a... more Excited conÿgurations are very important in dense plasma physics. In this work we propose a new analytical potential for excited conÿgurations obtained from another one for ground conÿguration. With this potential several atomic magnitudes have been calculated for ions in excited conÿgurations analyzing what kind of excited conÿgurations introduce more in uences in those magnitudes. Using this potential, atomic data generated are satisfactorily compared with those obtained using other analytical potential using sophisticated self-consistent codes, and with others available in the bibliography. ?

Research paper thumbnail of A screened hydrogenic model using analytical potentials

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

The screened hydrogenic model and analytical potentials are tools widely used for atomic calculat... more The screened hydrogenic model and analytical potentials are tools widely used for atomic calculation of dense plasma physics. In this paper, we present a simple method to obtain screened hydrogenic energy levels and wave functions from analytical potentials for ions. Atomic data obtained using this model are compared satisfactorily with results of similar models and of more sophisticated self-consistent codes.

Research paper thumbnail of An effective analytical potential including plasma effects

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

In this work, we have developed a method to build an e ective analytical potential for ions in sl... more In this work, we have developed a method to build an e ective analytical potential for ions in slightly nonideal plasmas. This proposed potential is obtained from an analytical isolated potential with one or two parameters depending on the total number of electrons of the ion. The plasma e ects are included by means of the linearized Debye-H uckel approximation taking into account the reaction of the plasma-charge density to the optical electron. Due to the in uence of the plasma over the atomic potential, this permits to obtain level energies and wave functions as a function of the inverse of Debye radius, the quantum numbers, the nuclear charge, the bound electron number and the ionization state of the ion. Also, we compare the analytical e ective potential proposed in this paper with other ones very well known in the available literature. ?

Research paper thumbnail of Low Z opacities at high densities

Journal of Quantitative Spectroscopy & Radiative Transfer, 2003

We present an experimental study devoted to measuring the opacity of bound-bound transitions in u... more We present an experimental study devoted to measuring the opacity of bound-bound transitions in ultra-dense, hot, low Z plasmas, which are at the extreme limit for conditions of both emission spectroscopy and absorption spectroscopy. In this work, we develop an absorption spectroscopy experiment specially adapted to high-density diagnostics, using newly designed structured targets and an ultra-high resolution spectrograph. An aluminum plasma is chosen as the ÿrst candidate and the opacity of the He-like 1s 2 -1s2p (Heÿ) and 1s 2 -1s3p (He ) transitions are measured. ?

Research paper thumbnail of A comparison of two atomic models for the radiative properties of dense hot low Z plasmas

Journal of Quantitative Spectroscopy & Radiative Transfer, 2003

In this work, two di erent atomic models (ANALOP based on parametric potentials and IDEFIX based ... more In this work, two di erent atomic models (ANALOP based on parametric potentials and IDEFIX based on the dicenter model) are used to calculate the opacities for bound-bound transitions in hot dense, low Z plasmas, and the results are compared to each other. In addition, the ANALOP code has been used to compute free-bound cross sections for hydrogen-like ions. ?

Research paper thumbnail of Relativistic quantum mechanic calculation of photoionization cross-section of hydrogenic and non-hydrogenic states using analytical potentials

Journal of Quantitative Spectroscopy & Radiative Transfer, 2005

Photoionization process is a subject of special importance in many areas of physics. Numerical me... more Photoionization process is a subject of special importance in many areas of physics. Numerical methods must be used in order to obtain photoionization cross-sections for non-hydrogenic levels. The atomic data required to calculate them is huge so self-consistent calculations increase computing time considerably. Analytical potentials are a useful alternative because they avoid the iterative procedures typical in self-consistent models. In this work, we present a relativistic quantum calculation of photoionization cross-sections for isolated ions based on an analytical potential to obtain the required atomic data, which is valid both for hydrogenic and non-hydrogenic ions. Comparisons between our results and others obtained using either widely used analytical expressions for the cross-sections or more sophisticated calculations are done.

Research paper thumbnail of Influence of the atomic description and configuration interaction effects on collisional-radiative calculations of low ionized carbon plasmas

Journal of Quantitative Spectroscopy & Radiative Transfer, 2009

An analysis of the influence of the atomic description and the configuration interaction effects ... more An analysis of the influence of the atomic description and the configuration interaction effects in the calculation of plasma average ionization and relevant plasma radiative properties such as the spectrally resolved emissivities and opacities, radiative power losses and mean opacities, is performed. Since the larger effects of the configuration interaction are due to the lower ionization stages, i.e. CI and

Research paper thumbnail of A screened hydrogenic model using analytical potentials

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

The screened hydrogenic model and analytical potentials are tools widely used for atomic calculat... more The screened hydrogenic model and analytical potentials are tools widely used for atomic calculation of dense plasma physics. In this paper, we present a simple method to obtain screened hydrogenic energy levels and wave functions from analytical potentials for ions. Atomic data obtained using this model are compared satisfactorily with results of similar models and of more sophisticated self-consistent codes.

Research paper thumbnail of Calculation of the radiative opacity of laser-produced plasmas using a relativistic-screened hydrogenic model

Journal of Quantitative Spectroscopy & Radiative Transfer, 2004

In this work, we use a relativistic-screened hydrogenic model to compute the radiative opacity of... more In this work, we use a relativistic-screened hydrogenic model to compute the radiative opacity of laserproduced plasmas. The model is based on a set of screening charges which allow one to easily calculate atomic properties of isolated ions. These screened charges have been ÿtted to a fourth-order polynomial depending on the nuclear charge Z for ground and single excited states of ions belonging to the isoelectronic sequences comprised between He-like to U-like. In the opacity model used, ionic populations are obtained by solving the Saha equation including degeneracy corrections. Bound-bound transitions are determined using a Voigt proÿle for line shape, which includes natural, collisional, Doppler and UTA widths. Bound-free and free-free opacities are evaluated using the Kramer cross-sections with appropriate corrections. Scattering processes are computed through the use of the Thomson formula with corrections. The results are compared with other screened hydrogenic models and more sophisticated self-consistent codes. ?

Research paper thumbnail of An effective analytical potential including plasma effects

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

In this work, we have developed a method to build an e ective analytical potential for ions in sl... more In this work, we have developed a method to build an e ective analytical potential for ions in slightly nonideal plasmas. This proposed potential is obtained from an analytical isolated potential with one or two parameters depending on the total number of electrons of the ion. The plasma e ects are included by means of the linearized Debye-H uckel approximation taking into account the reaction of the plasma-charge density to the optical electron. Due to the in uence of the plasma over the atomic potential, this permits to obtain level energies and wave functions as a function of the inverse of Debye radius, the quantum numbers, the nuclear charge, the bound electron number and the ionization state of the ion. Also, we compare the analytical e ective potential proposed in this paper with other ones very well known in the available literature. ?

Research paper thumbnail of Development of an analytical potential to include excited configurations

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

Excited conÿgurations are very important in dense plasma physics. In this work we propose a new a... more Excited conÿgurations are very important in dense plasma physics. In this work we propose a new analytical potential for excited conÿgurations obtained from another one for ground conÿguration. With this potential several atomic magnitudes have been calculated for ions in excited conÿgurations analyzing what kind of excited conÿgurations introduce more in uences in those magnitudes. Using this potential, atomic data generated are satisfactorily compared with those obtained using other analytical potential using sophisticated self-consistent codes, and with others available in the bibliography. ?

Research paper thumbnail of ANALYTICAL EXPRESSIONS FOR THE n-ORDER MOMENTA OF CHARGE DISTRIBUTION FOR IONS

Journal of Quantitative Spectroscopy & Radiative Transfer, 1998

In this work a family of four analytic expressions for the n-order momenta of the charge distribu... more In this work a family of four analytic expressions for the n-order momenta of the charge distribution for ions, 〈rn〉, depending on three, two, or one parameters will be presented. These expressions are derived through the use of electronic charge densities obtained from a family of four analytical potentials. The parameters in the expressions were obtained for ions in the

Research paper thumbnail of Calculation of the radiative opacity of laser-produced plasmas using a relativistic-screened hydrogenic model

Journal of Quantitative Spectroscopy & Radiative Transfer, 2004

In this work, we use a relativistic-screened hydrogenic model to compute the radiative opacity of... more In this work, we use a relativistic-screened hydrogenic model to compute the radiative opacity of laserproduced plasmas. The model is based on a set of screening charges which allow one to easily calculate atomic properties of isolated ions. These screened charges have been ÿtted to a fourth-order polynomial depending on the nuclear charge Z for ground and single excited states of ions belonging to the isoelectronic sequences comprised between He-like to U-like. In the opacity model used, ionic populations are obtained by solving the Saha equation including degeneracy corrections. Bound-bound transitions are determined using a Voigt proÿle for line shape, which includes natural, collisional, Doppler and UTA widths. Bound-free and free-free opacities are evaluated using the Kramer cross-sections with appropriate corrections. Scattering processes are computed through the use of the Thomson formula with corrections. The results are compared with other screened hydrogenic models and more sophisticated self-consistent codes. ?

Research paper thumbnail of Development of an analytical potential to include excited configurations

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

Excited conÿgurations are very important in dense plasma physics. In this work we propose a new a... more Excited conÿgurations are very important in dense plasma physics. In this work we propose a new analytical potential for excited conÿgurations obtained from another one for ground conÿguration. With this potential several atomic magnitudes have been calculated for ions in excited conÿgurations analyzing what kind of excited conÿgurations introduce more in uences in those magnitudes. Using this potential, atomic data generated are satisfactorily compared with those obtained using other analytical potential using sophisticated self-consistent codes, and with others available in the bibliography. ?

Research paper thumbnail of A screened hydrogenic model using analytical potentials

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

The screened hydrogenic model and analytical potentials are tools widely used for atomic calculat... more The screened hydrogenic model and analytical potentials are tools widely used for atomic calculation of dense plasma physics. In this paper, we present a simple method to obtain screened hydrogenic energy levels and wave functions from analytical potentials for ions. Atomic data obtained using this model are compared satisfactorily with results of similar models and of more sophisticated self-consistent codes.

Research paper thumbnail of An effective analytical potential including plasma effects

Journal of Quantitative Spectroscopy & Radiative Transfer, 2002

In this work, we have developed a method to build an e ective analytical potential for ions in sl... more In this work, we have developed a method to build an e ective analytical potential for ions in slightly nonideal plasmas. This proposed potential is obtained from an analytical isolated potential with one or two parameters depending on the total number of electrons of the ion. The plasma e ects are included by means of the linearized Debye-H uckel approximation taking into account the reaction of the plasma-charge density to the optical electron. Due to the in uence of the plasma over the atomic potential, this permits to obtain level energies and wave functions as a function of the inverse of Debye radius, the quantum numbers, the nuclear charge, the bound electron number and the ionization state of the ion. Also, we compare the analytical e ective potential proposed in this paper with other ones very well known in the available literature. ?