Isonuclear sequences in atomic spectroscopy

The notion of isonuclear sequences is employed in this work for studying the p shell on Na, Mg, Al, Si. Observed Regularities of the ionization potentials and Slater's integrals are reported.En este trabajo la noción de secuencias isonucleares es empleada para estudiar la capa pen Na, Mg, Al y Si. Ciertas regularidades observadas en las potenciales de ionización e integrales de Slater son reportadas

The Voigt Profile as a Sum of a Gaussian and a Lorentzian Functions, when the Weight Coefficient Depends on the Widths Ratio and the Independent Variable

Assuming that V (x) ≈ (1 − µ) G₁(x) + µL₁(x) is a very good approximation of the Voigt function, in this work we analytically find µ from mathematical properties of V (x). G₁(x) and L₁(x) represent a Gaussian and a Lorentzian function, respectively, with the same height and HWHM as V (x), the Voigt function, x being the distance from the function center. In this paper we extend the analysis that we have done in a previous paper, where µ is only a function of a; a being the ratio of the Lorentz width to the Gaussian width. Using one of the differential equation that V (x) satisfies, in the present paper we obtain µ as a function, not only of a, but also of x. Kielkopf first proposed µ(a, x) based on numerical arguments. We find that the Voigt function calculated with the expression µ(a, x) we have obtained in this paper, deviates from the exact value less than µ(a) does, specially for high |x| values.Facultad de Ciencias Astronómicas y GeofísicasInstituto de Astrofísica de La Plat

The Voigt Profile as a Sum of a Gaussian and a Lorentzian Functions, when the Weight Coefficient Depends Only on the Widths Ratio

Assuming that V (x) ≈ (1 − µ) G1(x) + µL1(x) is a very good approximation of the Voigt function, in this work we analytically find µ from mathematical properties of V (x). G1(x) and L1(x) represent a Gaussian and a Lorentzian function, respectively, with the same height and HWHM as V (x), the Voigt function, x being the distance from the fufind that, the Voigt function calculated with the expression we have obtained for µ, deviates from the exact value less than 0.5% with respect to the peak value.Instituto de Astrofísica de La Plat

Classified lines in the spectrum of Xe II

The spectrum of xenón emitted by a non-conventional light source has been studied. About 123 lines are classified in the range 2100 - 6750 AHa sido estudiado el espectro del xenón emitido por una fuente luminosa no convencional. Son clasificadas alrededor de 123 líneas en el rango de 2100 - 6750

Spectrum of Doubly Ionized Xenon (Xe III)

The spectrum of doubly ionized xenon has been investigated. The study is based on photographic recordings of xenon spectra in the 490-8900 Å range. The number of classified lines has been increased from about 300 to about 1400. The lines have been classified as transitions between 73 even levels belonging to the 5s25p4, 5s25p36p, 4ϕ, 5ϕ and 5s05p6 configurations, and 83 odd levels belonging to the 5s5p5, 5s25p36s, 7s, 5d and 6d configurations. In particular, the classifications include most of the Xe III laser lines. The experimentally observed level structures are compared with the results of Hartree-Fock calculations and least-squares fits. A comparison is also made between the results of the present analysis and the published data on the Xe N4,5OO Auger spectrumFacultad de Ciencias ExactasCentro de Investigaciones Óptica

Ionic assignment of Xe IV lines

The Xe IV spectrum between 2280 and 6100 A emitted by a new model of a non conventional spectroscopic «ource, has been studied. Six hundred and sixty «even lines has been assigned to this ion by employing the conventional method of energy variation, and the characteristic form of the spectral lines resulting from this type of spectral lamp has been particularly considered.El espectro del Xe IV entre 2280 y 6100 A emitido por un nuevo modelo de fuente espectroscópica no—convencional, ha sido estudiado. Seiscientas sesenta y siete líneas han sido asignadas a este ion, empleando el método convencional de variación de energía, y ha sido particularmente considerada la forma característica de las líneas espectrales que resultan de este tipo de fuente espectral

Spectrum of Doubly Ionized Xenon (Xe III)

The spectrum of doubly ionized xenon has been investigated. The study is based on photographic recordings of xenon spectra in the 490-8900 Å range. The number of classified lines has been increased from about 300 to about 1400. The lines have been classified as transitions between 73 even levels belonging to the 5s25p4, 5s25p36p, 4ϕ, 5ϕ and 5s05p6 configurations, and 83 odd levels belonging to the 5s5p5, 5s25p36s, 7s, 5d and 6d configurations. In particular, the classifications include most of the Xe III laser lines. The experimentally observed level structures are compared with the results of Hartree-Fock calculations and least-squares fits. A comparison is also made between the results of the present analysis and the published data on the Xe N4,5OO Auger spectrumFacultad de Ciencias ExactasCentro de Investigaciones Óptica

Evaluation of self-absorption of manganese emission lines in Laser Induced Breakdown Spectroscopy measurements

This paper is part of a more general study aimed to the determination of the best experimental procedures for reliable quantitative measurements of Fe-Mn alloys by LIBS. In this work, attention is pointed on the self-absorption processes, whose effect deeply influences the LIBS measurements, reflecting in non-linear calibration curves. The effect of self-absorption on the line intensity can be quantified by defining a self absorption coefficient, that measures the deviation of the line intensity from the linear extrapolation of the curve of growth in the optically thin regime. The authors demonstrated in a previous paper that self absorption coefficients could be calculated once the electron density of the plasma is known and the Stark coefficients of the lines are available. However, when the Stark coefficients of the lines of interest are not known, a different approach is needed. In this work a new method for evaluation of self absorption coefficients in LIBS measurements is presented, which does not require the knowledge of Stark coefficients. In order to understand the basic principles and setting out the theoretical tools that will be used for the analysis o f the alloys, a preliminary study was done on pure Mn; LIBS spectra were acquired in different experimental conditions, at different laser energies and different delays after the laser irradiation o f the sample. Moreover, collinear double pulse measurements were also performed. Analytical relations were derived and experimental procedures devised for evaluation o f the self absorption coefficients of several Mn lines, which are important for characterization and control of the experimental conditions in which the analysis is performed

Speckle interferometry applied to pharmacodynamic studies: evaluation of parasite motility

The work reported here describes the application of the optical technique known as dynamic speckle interferometry to evaluate the motility of nematode parasites exposed to different anthelmintic drugs. This technique, a well proven tool for assessing the time evolution of different phenomena, is here successfully used to quantify parasite motility in pharmacodynamic assays. The characterization of the pharmacological properties of anthelmintic drugs is critical to optimize their use in parasite control. Besides, the evaluation of nematode motility is a relevant indicator of the pharmacodynamic effect of anthelmintic drugs. The application of this approach to study the motility of Haemonchus contortus (used as a model of nematode parasites) larvae exposed to different drugs is presented, showing its usefulness.Facultad de IngenieríaCentro de Investigaciones Óptica

Ángulos planos: Por qué el radián debe tener una medida igual a la unidad?

In this article is discussed a subject that generates controversies inthe teaching of Physics: why the radian must be the correct unitfor the measurements of plane angles. The answer is, in ouropinion, in the concepts of Calculus, where the analytical notionsare independent of the geometrical ones.http://dx.doi.org/10.5007/2175-7941.2009v26n1p136En este artículo se trata de un asunto que genera polémicas en la enseñanza de la Física: por qué el radián debe tener asignada una medida igual a la unidad. El radián no es una de las tantas posibles unidades de ángulos, sino la única para la cual se cumplen las relaciones trigonométricas y del Cálculo Infinitesimal, aunque la Geometría Analítica no necesite de esta unidad. Se muestra que la respuesta debe buscarse en algunos sencillos conceptos del Cálculo Infinitesimal, donde las nociones analíticas se hacen independientes de las geométricas