Abstract
The shape of the powder pattern of the center resonance line (M= 1/2 {r_reversible} -1/2) for electron paramagnetic resonance (EPR) in orthorhombic symmetry, or nuclear magnetic resonance (NMR) with quadrupole interaction, is determined for all values of the crystal field symmetry parameter N by means of a general analytical method developed by Beltran-Lopez and Castro-Tello. Analytical functions in terms of elliptical integrals are obtained which are good approximations to the true powder pattern except in a narrow region around the field value corresponding to E=-2n{sup 2}/3. numerical gaussian quadrature of the powder pattern from the single-variable integral arising in the analytical method is shown to be a very efficient semianalytical method of calculation for computer work, being much smoother and requiring only a few seconds of CPU time versus the several minutes needed with the grid of the Monte Carlo methods. The semianalytical powder patterns reveal the existence of a previous unknown EPR spectral feature in orthorhombic symmetry resembling a divergence. This feature which should appear at E=-2n{sup 2}/3 for asymmetry parameter values near N={radical} of 2/3, is hidden in the experimental spectra by the broadening effect of the linewidth of the individual crystallites. Comparison of experimental and simulated spectra
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Citation Formats
Gonzalez-Tovany, L.
Accurate powder patterns and new spectral shape in orthorrombic symmetry; Patrones de polvo precisos y nuevos rasgos espectrales en simetria ortorrombica.
Mexico: N. p.,
1991.
Web.
Gonzalez-Tovany, L.
Accurate powder patterns and new spectral shape in orthorrombic symmetry; Patrones de polvo precisos y nuevos rasgos espectrales en simetria ortorrombica.
Mexico.
Gonzalez-Tovany, L.
1991.
"Accurate powder patterns and new spectral shape in orthorrombic symmetry; Patrones de polvo precisos y nuevos rasgos espectrales en simetria ortorrombica."
Mexico.
@misc{etde_10128049,
title = {Accurate powder patterns and new spectral shape in orthorrombic symmetry; Patrones de polvo precisos y nuevos rasgos espectrales en simetria ortorrombica}
author = {Gonzalez-Tovany, L}
abstractNote = {The shape of the powder pattern of the center resonance line (M= 1/2 {r_reversible} -1/2) for electron paramagnetic resonance (EPR) in orthorhombic symmetry, or nuclear magnetic resonance (NMR) with quadrupole interaction, is determined for all values of the crystal field symmetry parameter N by means of a general analytical method developed by Beltran-Lopez and Castro-Tello. Analytical functions in terms of elliptical integrals are obtained which are good approximations to the true powder pattern except in a narrow region around the field value corresponding to E=-2n{sup 2}/3. numerical gaussian quadrature of the powder pattern from the single-variable integral arising in the analytical method is shown to be a very efficient semianalytical method of calculation for computer work, being much smoother and requiring only a few seconds of CPU time versus the several minutes needed with the grid of the Monte Carlo methods. The semianalytical powder patterns reveal the existence of a previous unknown EPR spectral feature in orthorhombic symmetry resembling a divergence. This feature which should appear at E=-2n{sup 2}/3 for asymmetry parameter values near N={radical} of 2/3, is hidden in the experimental spectra by the broadening effect of the linewidth of the individual crystallites. Comparison of experimental and simulated spectra obtained by convoluting powder patterns with first-derivate lorentzian lineshapes of convenient width are also shown. Semianalytical spectra are much smoother than Monte Carlo simulated spectra, revealing finer spectral features. (Author).}
place = {Mexico}
year = {1991}
month = {Dec}
}
title = {Accurate powder patterns and new spectral shape in orthorrombic symmetry; Patrones de polvo precisos y nuevos rasgos espectrales en simetria ortorrombica}
author = {Gonzalez-Tovany, L}
abstractNote = {The shape of the powder pattern of the center resonance line (M= 1/2 {r_reversible} -1/2) for electron paramagnetic resonance (EPR) in orthorhombic symmetry, or nuclear magnetic resonance (NMR) with quadrupole interaction, is determined for all values of the crystal field symmetry parameter N by means of a general analytical method developed by Beltran-Lopez and Castro-Tello. Analytical functions in terms of elliptical integrals are obtained which are good approximations to the true powder pattern except in a narrow region around the field value corresponding to E=-2n{sup 2}/3. numerical gaussian quadrature of the powder pattern from the single-variable integral arising in the analytical method is shown to be a very efficient semianalytical method of calculation for computer work, being much smoother and requiring only a few seconds of CPU time versus the several minutes needed with the grid of the Monte Carlo methods. The semianalytical powder patterns reveal the existence of a previous unknown EPR spectral feature in orthorhombic symmetry resembling a divergence. This feature which should appear at E=-2n{sup 2}/3 for asymmetry parameter values near N={radical} of 2/3, is hidden in the experimental spectra by the broadening effect of the linewidth of the individual crystallites. Comparison of experimental and simulated spectra obtained by convoluting powder patterns with first-derivate lorentzian lineshapes of convenient width are also shown. Semianalytical spectra are much smoother than Monte Carlo simulated spectra, revealing finer spectral features. (Author).}
place = {Mexico}
year = {1991}
month = {Dec}
}