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Molecular Dynamics Investigated by Neutron Scattering; Etude de la Dynamique Moleculaire au Moyen de la Diffusion des Neutrons; 0418 0421 0421 041b 0415 0414 041e 0412 0410 041d 0418 0415 041c 041e 041b 0415 041a 0423 041b 042f 0420 041d 041e 0419 0414 0418 041d 0410 041c 0418 041a 0418 0421 041f 041e 041c 041e 0429 042c 042e 0420 0410 0421 0421 0415 042f 041d 0418 042f 041d 0415 0419 0422 0420 041e 041d 041e 0412 ; Estudio de la Dinamica Molecular por Dispersion Neutronica

Conference:

Abstract

A short review of the present state of the problem of applicability of the Krieger-Nelkin theory as well as of the Griffing theory to gases is made. Then, on the basis of experiments with liquid methane, the applicability of the mass-tensor concept to molecules in condensed states is criticized. Strong arguments against the application of the Krieger-Nelkin theory to condensed states are: a shift of neutron energy distribution after scattering towards higher energies and the lack of dependence of the Inelastic part on the scattering angle. Further sections deal with the rotational dynamics of ammonium groups in ammonium compounds. Most of the experimental material is discussed in connection with ammonium halides on the basis of experiments by different authors. For some substances a freedom of rotation of NH{sub 4} groups was obtained from neutron measurements, whereas for some others the rotation goes over into torsional vibration. In this case, frequencies of torsional vibrations obtained by various authors from neutron experiments were compared with those obtained from infrared spectroscopy and specific heat measurements. The barrier-to-rotation evaluation from total neutron cross-section measurements is also discussed. Further a comparison is made of the rotational dynamics of NH{sub 4} groups in NH{sub 4}CIO{sub 4}  More>>
Authors:
Janik, J. A. [1] 
  1. Institute for Nuclear Physics, Cracow (Poland)
Publication Date:
Jun 15, 1965
Product Type:
Conference
Report Number:
IAEA-SM-58/56
Resource Relation:
Conference: Symposium on Inelastic Scattering of Neutrons, Bombay (India), 15-19 Dec 1964; Other Information: 89 refs., 29 figs., 2 tabs.; Related Information: In: Inelastic Scattering of Neutrons. Vol. II. Proceedings of the Symposium on Inelastic Scattering of Neutrons| 590 p.
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ABSORPTION SPECTROSCOPY; AMMONIUM HALIDES; AMMONIUM PERCHLORATES; CROSS SECTIONS; CRYSTAL LATTICES; ENERGY SPECTRA; INELASTIC SCATTERING; INFRARED SPECTRA; METHANE; MOLECULAR DYNAMICS METHOD; NELKIN THEORY; NEUTRON DIFFRACTION; NUCLEAR MAGNETIC RESONANCE; RAMAN SPECTROSCOPY; ROTATION; SPECIFIC HEAT
OSTI ID:
22184056
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M3400008591
Submitting Site:
INIS
Size:
page(s) 243-276
Announcement Date:
Jan 30, 2014

Conference:

Citation Formats

Janik, J. A. Molecular Dynamics Investigated by Neutron Scattering; Etude de la Dynamique Moleculaire au Moyen de la Diffusion des Neutrons; 0418 0421 0421 041b 0415 0414 041e 0412 0410 041d 0418 0415 041c 041e 041b 0415 041a 0423 041b 042f 0420 041d 041e 0419 0414 0418 041d 0410 041c 0418 041a 0418 0421 041f 041e 041c 041e 0429 042c 042e 0420 0410 0421 0421 0415 042f 041d 0418 042f 041d 0415 0419 0422 0420 041e 041d 041e 0412 ; Estudio de la Dinamica Molecular por Dispersion Neutronica. IAEA: N. p., 1965. Web.
Janik, J. A. Molecular Dynamics Investigated by Neutron Scattering; Etude de la Dynamique Moleculaire au Moyen de la Diffusion des Neutrons; 0418 0421 0421 041b 0415 0414 041e 0412 0410 041d 0418 0415 041c 041e 041b 0415 041a 0423 041b 042f 0420 041d 041e 0419 0414 0418 041d 0410 041c 0418 041a 0418 0421 041f 041e 041c 041e 0429 042c 042e 0420 0410 0421 0421 0415 042f 041d 0418 042f 041d 0415 0419 0422 0420 041e 041d 041e 0412 ; Estudio de la Dinamica Molecular por Dispersion Neutronica. IAEA.
Janik, J. A. 1965. "Molecular Dynamics Investigated by Neutron Scattering; Etude de la Dynamique Moleculaire au Moyen de la Diffusion des Neutrons; 0418 0421 0421 041b 0415 0414 041e 0412 0410 041d 0418 0415 041c 041e 041b 0415 041a 0423 041b 042f 0420 041d 041e 0419 0414 0418 041d 0410 041c 0418 041a 0418 0421 041f 041e 041c 041e 0429 042c 042e 0420 0410 0421 0421 0415 042f 041d 0418 042f 041d 0415 0419 0422 0420 041e 041d 041e 0412 ; Estudio de la Dinamica Molecular por Dispersion Neutronica." IAEA.
@misc{etde_22184056,
title = {Molecular Dynamics Investigated by Neutron Scattering; Etude de la Dynamique Moleculaire au Moyen de la Diffusion des Neutrons; 0418 0421 0421 041b 0415 0414 041e 0412 0410 041d 0418 0415 041c 041e 041b 0415 041a 0423 041b 042f 0420 041d 041e 0419 0414 0418 041d 0410 041c 0418 041a 0418 0421 041f 041e 041c 041e 0429 042c 042e 0420 0410 0421 0421 0415 042f 041d 0418 042f 041d 0415 0419 0422 0420 041e 041d 041e 0412 ; Estudio de la Dinamica Molecular por Dispersion Neutronica}
author = {Janik, J. A.}
abstractNote = {A short review of the present state of the problem of applicability of the Krieger-Nelkin theory as well as of the Griffing theory to gases is made. Then, on the basis of experiments with liquid methane, the applicability of the mass-tensor concept to molecules in condensed states is criticized. Strong arguments against the application of the Krieger-Nelkin theory to condensed states are: a shift of neutron energy distribution after scattering towards higher energies and the lack of dependence of the Inelastic part on the scattering angle. Further sections deal with the rotational dynamics of ammonium groups in ammonium compounds. Most of the experimental material is discussed in connection with ammonium halides on the basis of experiments by different authors. For some substances a freedom of rotation of NH{sub 4} groups was obtained from neutron measurements, whereas for some others the rotation goes over into torsional vibration. In this case, frequencies of torsional vibrations obtained by various authors from neutron experiments were compared with those obtained from infrared spectroscopy and specific heat measurements. The barrier-to-rotation evaluation from total neutron cross-section measurements is also discussed. Further a comparison is made of the rotational dynamics of NH{sub 4} groups in NH{sub 4}CIO{sub 4} and H{sub 3}O groups in H{sub 3}OCIO{sub 4} on the basis of neutron inelastic scattering experiments. A free rotation of the NH{sub 4} group in ammonium perchlorate was obtained even at temperatures as low as liquid nitrogen temperature. For H{sub 3}OCIO{sub 4} a torsional vibration of the H{sub 3}O group with a frequency of 497 cm{sup -1} was obtained. So in spite of the identity of the crystal lattices of NH{sub 4}CIO{sub 4} and H{sub 3}OCIO{sub 4} the dynamics of the NH{sub 4} and H{sub 3}O groups are different. The results are compared with those known from Raman spectroscopy and nuclear magnetic resonance. Finally, a number of other substances is discussed from the point of view of molecular dynamics. (author) [French] L'auteur fait le point de l'etat actuel des connaissances touchant le probleme de l'applicabilite des theories de Krieger- Nelkin et de Griffing dans le cas des gaz. Ensuite, sur la base d'experiences faites avec du methane liquide, il examine d'une maniere critique l'applicabilite du concept du tenseur de masse a des molecules dans l'etat condense. Les arguments les plus puissants qui militent contre l'application de la theorie de Krieger-Nelkin aux etats condenses sont: a) un deplacement dans la distribution des neutrons en energie, apres diffusion, vers les grandes energies; b) l'absence d'une relation de dependance entre la fraction inelastique et l'angle de diffusion. D'autres parties du memoire traitent de la dynamique de rotation des groupes ammonium dans les composes d'ammonium. L'auteur discute la plupart des donnees d'experience relatives aux halogenures d'ammonium en se fondant sur les experiences de differents auteurs. Far des mesures de neutrons, il a obtenu une liberte de rotation des groupes NH{sub 4} pour certaines substances, tandis que pour d'autres la rotation evolue en vibration de torsion. Dans le dernier cas, il a compare les frequences des vibrations de torsion obtenues par divers auteurs au cours d'experiences sur les neutrons avec celles qui resultent de la spectroscopie infrarouge et des mesures de la chaleur specifique. L'auteur discute egalement l'obstacle qui s'oppose a l'evaluation de la rotation a l'aide de mesures des sections efficaces totales pour les neutrons. En outre, il compare la dynamique de rotation des groupes NH{sub 4} dans NH{sub 4}ClO{sub 4} et des groupes H{sub 3}O dans H{sub 3}OCIO{sub 4}, en se fondant sur des experiences de diffusion inelastique des neutrons. Il a obtenu une rotation libre du groupe NH4 dans le perchlorate d'ammonium, meme a des temperatures ne depassant pas celle de l'azote liquide. Pour H{sub 3}OCIO{sub 4} il a obtenu une vibration de torsion du groupe H{sub 3}O avec une frequence de 497 cm{sup -1}. Il s'ensuit que, malgre l'identite des reseaux cristallins de NH{sub 4}CIO{sub 4} et H{sub 3}OCIO{sub 4} la dynamique des groupes NH{sub 4} et H{sub 3}O est differente. L'auteur compare ces resultats avec ceux qui ont ete obtenus par spectroscopie de Raman et resonance magnetique nucleaire. Enfin, il discute plusieurs autres substances du point de vue de la dynamique moleculaire. (author) [Spanish] Se examina brevemente en que medida la teoria de Krieger-Nelkin y la de Griffing son aplicables a los gases. A continuacion, y sobre la base de experimentos realizados con metano liquido, se hace un estudio critico de la posibilidad de aplicar el concepto de tensor rriasico a las moleculas en estado condensado. Los principales argumentos en contra de la aplicacion de la teoria de Krieger y Nelkin a los estados condensados son: el desplazamiento hacia energias mas elevadas de la distribucion de las energias neutronicas a raiz de la dispersion y la independencia de la parte inelastica con respecto al angulo de dispersion. Se estudia tambien la dinamica de rotacion de los grupos amonio en compuestos amonicos. Se examina gran parte de los datos experimentales obtenidos por diferentes autores sobre los haluros de amonio. Para algunas sustancias, las mediciones efectuadas mediante dispersion neutronica indican la libertad de rotacion del grupo NH{sub 4}, mientras que para otras, la rotacion se transforma en una vibracion torsional. En este caso, las frecuencias de las vibraciones torsionales que diferentes autores han obtenido por dispersion neutronica se comparan con las determinadas por espectroscopia infrarroja y medicion del calor especifico. Se estudia tambien el calculo basado en la medicion de la seccion eficaz neutronica total de la barrera que se opone a la rotacion. Asimismo, se compara la dinamica de rotacion de los grupos NH{sub 4} en el NH{sub 4}CIO{sub 4} y de los grupos H{sub 3}O en el H{sub 3}OClO{sub 4} sobre la base de experimentos de dispersion inelastica de neutrones. Los resultados obtenidos indican que la rotacion del grupo NH4 en el perclorato amonico es libre, incluso a temperaturas tan bajas como la del nitrogeno liquido. En lo que respecta al H{sub 3}OClO{sub 4}, se ha observado una vibracion torsional del grupo H{sub 3}O con una frecuencia de 497 cm{sup -1}. Por tanto, a pesar de la identidad de las redes cristalinas del NH{sub 4}CIO{sub 4} y del H{sub 3}OCIO{sub 4}, la dinamica de los grupos NH{sub 4} es diferente de la de los grupos H{sub 3}O. Los resultados se comparan con los obtenidos por espectroscopia Raman y resonancia magnetica nuclear. Por ultimo, se estudia una serie de sustancias desde el punto de vista de su dinamica molecular. (author) [Russian] Kratko rassmatrivaetsja polozhenie s voprosom o primenimosti teorii Krigera- Nel'kina i teorii Griffinga v otnoshenii gazov. Zatem na osnovanii jeksperimentov s zhidkim metanom kriticheski rassmatrivaetsja vopros o primenimosti koncepcii tenzora massy v otnoshenii molekul v kondensirovannom sostojanii. Ubeditel'nymi dovodami protiv primenenija teorii Krigera-Nel'kina v otnoshenii kondensirovannyh sostojanij javljajutsja: sdvig raspredelenija jenergii nejtronov posle rassejanija v storonu bolee vysokih jenergij i otsutstvie zavisimosti neuprugoj chasti ot ugla rassejanija. Sledujushhie razdely posvjashheny rotacionnoj dinamike ammonievyh grupp v soedinenijah ammonija. Bol'shaja chast' jeksperimental'nogo materiala rassmatrivaetsja v svjazi s galoidami ammonija, ishodja iz rezul'tatov jeksperimentov razlichnyh avtorov. Dlja nekotoryh veshhestv svoboda vrashhenija grupp NH{sub 4} poluchena na osnovanii izmerenija nejtronov, togda kak dlja nekotoryh drugih jeto vrashhenie perehodit v krutil'noe kolebanie. V jetom sluchae chastoty krutil'nyh kolebanij, poluchennye razlichnymi avtorami v rezul'tate izmerenija nejtronov, sravnivalis' s chastotami, poluchennymi s pomoshh'ju infrakrasnoj spektroskopii i izmerenij udel'noj teploemkosti. Rassmatrivaetsja takzhe vopros o predele vozmozhnosti ocenki vrashhenija na osnovanii rezul'tatov izmerenija obshhih nejtronnyh sechenij. Krome togo proizvoditsja sravnenie vrashhatel'noj dinamiki grupp NH{sub 4} v NH{sub 4}CIO{sub 4} i grupp H{sub 3}O v H{sub 3}OCIO{sub 4} na osnove rezul'tatov jeksperimentov po neuprugomu rassejaniju nejtronov. Svobodnoe vrashhenie gruppy NH4 v hlornokislom ammonii bylo polucheno dazhe pri takih nizkih temperaturah, kak temperatura zhidkogo azota. Dlja H{sub 3}OCIO{sub 4} bylo obnaruzheno krutil'noe kolebanie gruppy N3O s chastotoj 497 sm{sup 1} . Takim obrazom, nesmotrja na identichnost' kristallicheskih reshetok NH{sub 4}CIO{sub 4} i H{sub 3}OCIO{sub 4}, dinamika grupp NH{sub 4} i H{sub 3}O javljaetsja razlichnoj. Jeti rezul'taty sravnivajutsja s rezul'tatami, poluchennymi s pomoshh'ju spektroskopii Ramana i jadernogo magnitnogo rezonansa. I, nakonec, rjad drugih veshhestv rassmatrivaetsja s tochki zrenija molekuljarnoj dinamiki. (author)}
place = {IAEA}
year = {1965}
month = {Jun}
}