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Chemical Effects of Nuclear Recoil in Organic Halide Systems: A New Theoretical Treatment and Experimental Verification of the Theory; Effets Chimiques du Recul Nucleaire dans des Systemes Organiques Halogenes: Nouveau Traitement Theorique et Verification Experimentale de la Theorie; Khimicheskie vozdejstviya yadernoj otdachi v organicheskikh galoidnykh sistemakh: novoe teoreticheskoe tolkovanie i ehksperimental'noe podtverzhdenie teorii; Efectos Quimicos del Retroceso Nuclear en Sistemas de Haluros Organicos: Nuevo Tratamiento Teorico y Verificacion Experimental de la Teoria

Conference:

Abstract

Methods have been developed for calculating the organic retention of radiohalogen to be expected following neutron activation of mixtures of two organic halides and the corresponding free halogen. The methods are based on the concepts of the Libby ''billiard-ball'' process of hot-atom labelling and retentions are expressed in terms of two types of parameters: (1) the fractional chance that collision of a hot radiohalogen atom with a particular molecule will lead to retention of the hot atom in that molecule; (2) the upper and lower energy limits for what is termed a hot bromine atom. It is shown how the former type of parameter may be derived from experiments with binary mixtures of an organic halide and the corresponding free halogen: the second type of parameter must be deduced from nuclear and chemical data. These methods have been tested by studies on the systems C{sub 2}H{sub 5}Br/CCl{sub 4}/Br{sub 2} and C{sub 2}H{sub 5}Br/C{sub 6}H{sub 5}Br/Br{sub 2}. The calculated retentions (using parameters derived from studies of the systems C{sub 2}H{sub 5}Br/Br{sub 2}, CCl{sub 4}/Br{sub 2} and C{sub 6}H{sub 5}Br/Br{sub 2}) are in good agreement with those found experimentally in mixtures with a bromine mole-fraction greater than about 0.1. It is therefore  More>>
Authors:
Kontis, S. S.; Sanitwongs, P.; Weston, M. [1] 
  1. Londonderry Laboratory for Radiochemistry, University of Durham, Durham (United Kingdom)
Publication Date:
Apr 15, 1965
Product Type:
Conference
Report Number:
IAEA-SM-57/36
Resource Relation:
Conference: Symposium on Chemical Effects Associated with Nuclear Reactions and Radioactive Transformations, Vienna (Austria), 7-11 Dec 1964; Other Information: 16 refs., 3 tab., 4 figs.; Related Information: In: Chemical Effects of Nuclear Transformations Vol. I. Proceedings of the Symposium on Chemical Effects Associated with Nuclear Reactions and Radioactive Transformations| 457 p.
Subject:
38 RADIATION CHEMISTRY, RADIOCHEMISTRY AND NUCLEAR CHEMISTRY; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ANTINEUTRON REACTIONS; ATOM-MOLECULE COLLISIONS; BINARY MIXTURES; BROMINE; CARBON TETRACHLORIDE; CHEMICAL RADIATION EFFECTS; CONCENTRATION RATIO; EXPERIMENTAL DATA; HALIDES; HOT ATOM CHEMISTRY; LABELLING; RECOILS; RETENTION; SCAVENGING; THEORETICAL DATA
OSTI ID:
22141777
Research Organizations:
International Atomic Energy Agency, Vienna (Austria); Joint Commission on Applied Radioactivity of the International Council of Scientific Unions, Paris (France)
Country of Origin:
IAEA
Language:
English
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M3307096378
Submitting Site:
INIS
Size:
page(s) 311-331
Announcement Date:
Oct 24, 2013

Conference:

Citation Formats

Kontis, S. S., Sanitwongs, P., and Weston, M. Chemical Effects of Nuclear Recoil in Organic Halide Systems: A New Theoretical Treatment and Experimental Verification of the Theory; Effets Chimiques du Recul Nucleaire dans des Systemes Organiques Halogenes: Nouveau Traitement Theorique et Verification Experimentale de la Theorie; Khimicheskie vozdejstviya yadernoj otdachi v organicheskikh galoidnykh sistemakh: novoe teoreticheskoe tolkovanie i ehksperimental'noe podtverzhdenie teorii; Efectos Quimicos del Retroceso Nuclear en Sistemas de Haluros Organicos: Nuevo Tratamiento Teorico y Verificacion Experimental de la Teoria. IAEA: N. p., 1965. Web.
Kontis, S. S., Sanitwongs, P., & Weston, M. Chemical Effects of Nuclear Recoil in Organic Halide Systems: A New Theoretical Treatment and Experimental Verification of the Theory; Effets Chimiques du Recul Nucleaire dans des Systemes Organiques Halogenes: Nouveau Traitement Theorique et Verification Experimentale de la Theorie; Khimicheskie vozdejstviya yadernoj otdachi v organicheskikh galoidnykh sistemakh: novoe teoreticheskoe tolkovanie i ehksperimental'noe podtverzhdenie teorii; Efectos Quimicos del Retroceso Nuclear en Sistemas de Haluros Organicos: Nuevo Tratamiento Teorico y Verificacion Experimental de la Teoria. IAEA.
Kontis, S. S., Sanitwongs, P., and Weston, M. 1965. "Chemical Effects of Nuclear Recoil in Organic Halide Systems: A New Theoretical Treatment and Experimental Verification of the Theory; Effets Chimiques du Recul Nucleaire dans des Systemes Organiques Halogenes: Nouveau Traitement Theorique et Verification Experimentale de la Theorie; Khimicheskie vozdejstviya yadernoj otdachi v organicheskikh galoidnykh sistemakh: novoe teoreticheskoe tolkovanie i ehksperimental'noe podtverzhdenie teorii; Efectos Quimicos del Retroceso Nuclear en Sistemas de Haluros Organicos: Nuevo Tratamiento Teorico y Verificacion Experimental de la Teoria." IAEA.
@misc{etde_22141777,
title = {Chemical Effects of Nuclear Recoil in Organic Halide Systems: A New Theoretical Treatment and Experimental Verification of the Theory; Effets Chimiques du Recul Nucleaire dans des Systemes Organiques Halogenes: Nouveau Traitement Theorique et Verification Experimentale de la Theorie; Khimicheskie vozdejstviya yadernoj otdachi v organicheskikh galoidnykh sistemakh: novoe teoreticheskoe tolkovanie i ehksperimental'noe podtverzhdenie teorii; Efectos Quimicos del Retroceso Nuclear en Sistemas de Haluros Organicos: Nuevo Tratamiento Teorico y Verificacion Experimental de la Teoria}
author = {Kontis, S. S., Sanitwongs, P., and Weston, M.}
abstractNote = {Methods have been developed for calculating the organic retention of radiohalogen to be expected following neutron activation of mixtures of two organic halides and the corresponding free halogen. The methods are based on the concepts of the Libby ''billiard-ball'' process of hot-atom labelling and retentions are expressed in terms of two types of parameters: (1) the fractional chance that collision of a hot radiohalogen atom with a particular molecule will lead to retention of the hot atom in that molecule; (2) the upper and lower energy limits for what is termed a hot bromine atom. It is shown how the former type of parameter may be derived from experiments with binary mixtures of an organic halide and the corresponding free halogen: the second type of parameter must be deduced from nuclear and chemical data. These methods have been tested by studies on the systems C{sub 2}H{sub 5}Br/CCl{sub 4}/Br{sub 2} and C{sub 2}H{sub 5}Br/C{sub 6}H{sub 5}Br/Br{sub 2}. The calculated retentions (using parameters derived from studies of the systems C{sub 2}H{sub 5}Br/Br{sub 2}, CCl{sub 4}/Br{sub 2} and C{sub 6}H{sub 5}Br/Br{sub 2}) are in good agreement with those found experimentally in mixtures with a bromine mole-fraction greater than about 0.1. It is therefore considered that the Libby mechanism is adequate to explain the observed organic retentions in such mixtures. As the bromine mole-fraction is reduced, below 0.1 the observed retentions become progressively higher than calculated values. This is attributed to there being additional modes of hot-atom labelling which become operative when the bromine concentration is not high enough to give adequate radical scavenging. (author) [French] Lesauteuts ont mis au point des methodes pour calculer la retention organique du radiohalogene a laquelle on peut s'attendre apres activation par les neutrons de melanges de deux halogenures organiques et de l'halogene libre correspondant. Ces methodes sont basees sur les principes du mecanisme de la 'boule de billard' pour le marquage par l'atome chaud, auquel Libby a donne son nom, et les retentions sont exprimees en fonction de deux types de parametres, savoir: 1. la probabilite que le choc entre un atome chaud de radiohalogene et une molecule donnee determine la retention de l'atome chaud dans cette molecule; 2. les limites superieure et inferieure des energies pour lesquelles un atome de brome est dit chaud. Les auteurs montrent comment le premier type de parametre peut etre derive d'experiences sur des melanges binaires d'un halogenure organique et de l'halogene libre correspondant; le second type de parametre doit etre deduit des constantes nucleaires et chimiques. Des etudes sur les systemes C{sub 2}H{sub 5}Br/CCl{sub 4}/Br{sub 2} et C{sub 2}H{sub 5}Br/C{sub 6}H{sub 5}Br/Br{sub 2} ont permis de faire l'essai de ces methodes. Les valeurs de retention calculees (en Utilisant des parametres derives d'etudes des systemes C{sub 2}H{sub 5}Br/Br{sub 2}, CCl{sub 4}/Br{sub 2} et C{sub 6}H{sub 5}Br/Br{sub 2}) concordent avec celles qui sont determinees experimentalement dans des melanges ou la fraction molaire de brome est superieure a 0,1 environ. Par consequent, les auteurs considerent que le mecanisme Libby permet d'expliquer les retentions organiques observees dans ces melanges. Lorsque la fraction molaire de brome devient inferieure a 0,1, les retentions observees augmentent progressivement par rapport aux valeurs calculees, ce qui est sans doute du au fait que d'autres modes de marquage par l'atome chaud interviennent lorsque la concentration en brome n'est pas assez elevee pour assurer un bon 'balayage' des radicaux. (author) [Spanish] Los autores elaboraron metodos para calcular la probable retencion organica de los halogenos radiactivos despues de activar con neutrones mezclas de dos haluros organicos y el correspondiente halogeno libre; Los metodos se basan en la teoria del proceso de ' bolas de billar ' de Hbby para la marcacion con atomos calientes; la retencion se expresa en funcion de dos tipos de parametros, a saber: 1) la probabilidad relativa de que ei choque de un atomo caliente de halogeno radiactivo con una molecula determinada produzca la retencion del atomo caliente en dicha molecula; 2) los limites energeticos superior e inferior dentro de los cuales el atomo de bromo puede considerarse caliente. Los autores demuestran como el primer tipo de parametro puede deducirse experimentalmente de mezclas binarias de un haluro organico y el correspondiente halogeno libre; el segundo tipo de parametro debe deducirse a partir de datos nucleares quimicos. Dichos metodos han sido ensayados en los sistemas C{sub 2}H{sub 5}Br/CCl{sub 4}/Br{sub 2} and C{sub 2}H{sub 5}Br/C{sub 6}H{sub 5}Br/Br{sub 2}. Los valores calculados para las retenciones (empleando parametros derivados del estudio de los sistemas C{sub 2}H{sub 5}Br/Br{sub 2}, CCl{sub 4}/Br{sub 2} and C{sub 6}H{sub 5}Br/Br{sub 2})) eoncuerdan satisfactoriamente con los dalos hallados experimentalmeme en mezclas cuya fraccion molar de bromo es superior a 0,1. De esta manera se considera que el mecanismo propuesto por Libby permite explicar las retenciones organicas observadas en dichas mezclas. Cuando la fraccion molar de bromo se va reduciendo a valores inferiores a 0,1, las retenciones observadas se hacen progresivamente mayores que los valores calculados. Este fenomeno se atribuye a la existencia de otros modos de marcacion con atomos calientes, que entran en juego cuando la concentracion de bromo no es bastante elevada para eliminar adecuadamente los radicales en virtud de mecanismos de depuracion. (author) [Russian] Byli razrabotany metody rascheta organicheskogo uderzhanija radiogalogenov, kotorye mozhno ozhidat' vsledstvie nejtronnoj aktivacii smesej dvuh organicheskih galoidov i sootvetstvujushhih svobodnyh galogenov. Jeti metody osnovany na koncepcijah processa ''bil'jardnogo shara'' Libbi po mecheniju gorjachih atomov, i uderzhanija vyrazhajutsja v vide dvuh tipov parametrov, a imenno: 1) frakcionnaja vozmozhnost' togo, chto stolknovenie gorjachego atoma radioaktivnogo galogena s kakoj-to opredelennoj molekuloj privedet k uderzhaniju gorjachego atoma v toj molekule; 2) verhnie i nizhnie predely jenergij dlja tak nazyvaemogo gorjachego atoma broma. Pokazyvaetsja, kak pervyj tip parametra mozhet byt' vyveden iz jeksperimentov s binarnymi smesjami organicheskogo galoidnogo soedinenija i sootvetstvujushhego svobodnogo galogena: vtoroj tip parametra dolzhen vyvodit'sja iz jadernyh i himicheskih dannyh. Jeti metody proverjalis' s pomoshh'ju issledovanij na sistemah C{sub 2}H{sub 5}Br/CCl{sub 4}/Br{sub 2} i C{sub 2}H{sub 5}Br/C{sub 6}H{sub 5}Br/Br{sub 2}. Vychislennye uderzhanija (s ispol'zovaniem parametrov, vyvedennyh iz issledovanij sistem C{sub 2}H{sub 5}Br/Br{sub 2}, CCl{sub 4}/Br{sub 2} i C{sub 6}H{sub 5}Br/Br{sub 2}) horosho soglasujutsja s uderzhanijami, najdennymi jeksperimental'no v smesjah s frakciej grammolekuly broma bol'she 0,1. Takim obrazom, polagajut, chto mehanizm Libbi javljaetsja podhodjashhim dlja ob'jasnenija nabljudaemyh organicheskih uderzhanij v takih smesjah. Esli frakcija grammolekuly broma opuskaetsja nizhe OD, nabljudaemye uderzhanija stanovjatsja v progressivnoj stepeni vyshe, chem rasschitannye velichiny. Jeto ob{sup j}asnjaetsja dopolnitel'nymi vidami mecheni* gorjachih atomov, kotorye stanovjatsja dejstvujushhimi, esli koncentracija broma ne javljaetsja dostatochno vysokoj, chtoby dat' sootvetstvujushhuju ochistku radikala. (author)}
place = {IAEA}
year = {1965}
month = {Apr}
}