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Lattice Dynamics of Magnesium; Dynamique de Reseau du Magnesium; Dinamika reshetki magniya; Dinamica Reticular del Magnesio

Conference:

Abstract

A group theoretical analysis of modes of vibrations in hexagonal close-packed lattices has been made. The results have been used to classify the phonons at some special points in the Brillouin zone and factorized the secular determinant. Dispersion relations for phonons in magnesium along the two symmetry directions [0001] and [0110] have been measured (at room temperature) more accurately than reported earlier. The measurements have been made using a triple-axis spectrometer and a ''window filter'' spectrometer, both operated in the ''constant-Q'' mode. The results are compared with calculations based on three- and four-neighbour axially symmetric models. It is observed that the four-neighbour model gives a reasonably good description of the data. Even better agreement is obtained with a four-neighbour tensor force model. The force constants derived from the experiment have been used to compute the frequency distribution. (author) [French] Les auteurs ont procede a une analyse theorique par groupe des niodes de vibration dans les reseaux a structure hexagonale compacte. Ils ont utilise les resultats pour classer les phonons en des points particuliers de la zone de Brillouin et analyser mathematiquement le determinant seculaire. Afin d'etablir les relations de dispersion pour les phonons du magnesium dans les deux directions de  More>>
Authors:
Iyengar, P. K.; Venkataraman, G.; Vuayaraghavan, P. R.; Roy, A. P. [1] 
  1. Atomic Energy Establishment Trombay, Bombay (India)
Publication Date:
Apr 15, 1965
Product Type:
Conference
Report Number:
IAEA-SM-58/24
Resource Relation:
Conference: Symposium on Inelastic Scattering of Neutrons, Bombay (India), 15-19 Dec 1964; Other Information: 26 refs., 8 figs., 4 tabs.; Related Information: In: Inelastic Scattering of Neutrons. Vol. I. Proceedings of the Symposium on Inelastic Scattering of Neutrons| 476 p.
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AXIAL SYMMETRY; BRILLOUIN ZONES; COMPARATIVE EVALUATIONS; DISPERSION RELATIONS; FREQUENCY DEPENDENCE; HCP LATTICES; MAGNESIUM; PHONONS; SPECTROMETERS; TEMPERATURE RANGE 0273-0400 K; TENSOR FORCES; THEORETICAL DATA
OSTI ID:
22141798
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M3364096399
Submitting Site:
INIS
Size:
page(s) 153-178
Announcement Date:
Oct 24, 2013

Conference:

Citation Formats

Iyengar, P. K., Venkataraman, G., Vuayaraghavan, P. R., and Roy, A. P. Lattice Dynamics of Magnesium; Dynamique de Reseau du Magnesium; Dinamika reshetki magniya; Dinamica Reticular del Magnesio. IAEA: N. p., 1965. Web.
Iyengar, P. K., Venkataraman, G., Vuayaraghavan, P. R., & Roy, A. P. Lattice Dynamics of Magnesium; Dynamique de Reseau du Magnesium; Dinamika reshetki magniya; Dinamica Reticular del Magnesio. IAEA.
Iyengar, P. K., Venkataraman, G., Vuayaraghavan, P. R., and Roy, A. P. 1965. "Lattice Dynamics of Magnesium; Dynamique de Reseau du Magnesium; Dinamika reshetki magniya; Dinamica Reticular del Magnesio." IAEA.
@misc{etde_22141798,
title = {Lattice Dynamics of Magnesium; Dynamique de Reseau du Magnesium; Dinamika reshetki magniya; Dinamica Reticular del Magnesio}
author = {Iyengar, P. K., Venkataraman, G., Vuayaraghavan, P. R., and Roy, A. P.}
abstractNote = {A group theoretical analysis of modes of vibrations in hexagonal close-packed lattices has been made. The results have been used to classify the phonons at some special points in the Brillouin zone and factorized the secular determinant. Dispersion relations for phonons in magnesium along the two symmetry directions [0001] and [0110] have been measured (at room temperature) more accurately than reported earlier. The measurements have been made using a triple-axis spectrometer and a ''window filter'' spectrometer, both operated in the ''constant-Q'' mode. The results are compared with calculations based on three- and four-neighbour axially symmetric models. It is observed that the four-neighbour model gives a reasonably good description of the data. Even better agreement is obtained with a four-neighbour tensor force model. The force constants derived from the experiment have been used to compute the frequency distribution. (author) [French] Les auteurs ont procede a une analyse theorique par groupe des niodes de vibration dans les reseaux a structure hexagonale compacte. Ils ont utilise les resultats pour classer les phonons en des points particuliers de la zone de Brillouin et analyser mathematiquement le determinant seculaire. Afin d'etablir les relations de dispersion pour les phonons du magnesium dans les deux directions de symetrie [0001] et [0110] (a la temperature ambiante), ils ont fait des mesures plus precises que celles qui ont ete signalees jusqu'a present. A cet effet, ils ont utilise un spectrometre triaxial et un spectrometre avec 'filtre a fenetre', l'un et l'autre dans le mode de 'Q constant'. Ils ont compare les resultats aux calculs fondes sur des modeles a symetrie axiale faisant intervenir les troisieme et quatrieme voisins. Ils ont constate que le deuxieme de ces modeles fournit une assez bonne description des donnees. Un modele de forces tensorielles englobant le quatrieme voisin assure une concordance encore meilleure. Les auteurs ont utilise les constantes de force deduites de l'experience pour calculer la distribution de frequence. (author) [Spanish] Los modos de vibracion de las redes hexagonales compactas se han analizado sobre la base de la teoria de los grupos. Los resultados se han utilizado para clasificar los fonones de algunos puntos especiales de la zona de Brillouin y para factorizar el determinante secular. Se han medido, con mayor precision que la alcanzada hasta el presente, las relaciones de dispersion de los fonones en el magnesio en dos direcciones de simetria [0001] y [0110], a la temperatura ambiente. Las mediciones se han efectuado utilizando un espectrometro triaxial y un espectrometro con 'filtro de ventana', funcionando ambos segun el modo de 'Q constante'. Los resultados se comparan con calculos basados en modelos axialmente simetricos que abarcan hasta el tercer o el cuarto atomo vecino. Se ha comprobado que este ultimo modelo se ajusta adecuadamente a los datos obtenidos. Con un modelo de fuerzas tensoriales que alcanzan hasta el cuarto atomo, se obtiene una concordancia aun mas satisfactoria. Para calcular la distribucion de frecuencias se han utilizado las constantes de fuerza deducidas del experimento. (author) [Russian] Byl proizveden gruppovoj teoreticheskij analiz vidov kolebanij v geksagonal'noj reshetke s plotnoj upakovkoj. Rezul'taty byli ispol'zovany dlja klassifikacii fononov v nekotoryh special'nyh tochkah zony Brillouina i razlozhenija vekovogo determinanta. Dispersionnye sootnoshenija dlja fononov v magnii v dvuh simmetrichnyh napralenijah [0001] i [0110] byli izmereny (pri komnatnoj temperature) bolee tochno, chem soobshhalos' ranee. Izmerenija byli proizvedeny s pomoshh'ju trehosnogo spektrometra i spektrometra s ''okonnym fil'trom''. Oba jeti spektrometra rabotali pri kolebanii s ''postojannym''. Rezul'taty izmerenij sopostavljajutsja s rezul'tatami raschetov, osnovannyh na treh- i chetyrehchlennyh aksial'no simmetrichnyh modeljah. Ustanovleno, chto chetyrehchlennaja model' daet dovol'no horoshee opisanie jetih dannyh. Eshhe bolee horoshee soglasie polucheno s chetyrehchlennoj model'ju tenzornoj sily. Konstanty sily, poluchennye v rezul'tate jeksperimentov, byli ispol'zovany dlja vychislenija raspredelenija chastot. (author)}
place = {IAEA}
year = {1965}
month = {Apr}
}