Published January 1963
| Version v1
Book
Dynamics of Liquid Hydrogen by Neutron Scattering
Creators
- 1. International Atomic Energy Agency, Vienna (Austria)
- 2. General Dynamics, General Atomic, San Diego, CA (United States)
Description
The total scattering cross-section of liquid para-hydrogen for neutrons below about 0.014 eV is found to conform approximately to the Schwinger-Teller theory for para-hydrogen gas, indicating very weak intermolecular forces. A minimum of about 3 b per hydrogen atom is reached at about 0.014 eV as a result of coherence of scattering from oppositely oriented atoms in the molecule. A sharp rise with increasing neutron energy above this threshold corresponds to inelastic collisions in which the neutron spin is reversed and the molecule is thus converted from para- to ortho-hydrogen, absorbing the energy difference between the J = 0 and J = 1 ground rotational levels of the para and ortho states. Preliminary measurements of the neutron energy loss in both energy regions confirm these interpretations and are being continued for more detailed investigation of liquid dynamics. (author)
Abstract (French)
La section efficace totale de diffusion des neutrons dans du para-hydrogene liquide pour une energie inferieure a 0,014 eV concorde approximativement avec les resultats donnes par la theorie de Schwinger-Teller pour le para-hydro- gene gazeux, ce qui montre que les forces intermoleculaires en presence sont tres faibles. Cette section efficace atteint un minimum d'environ 3 b par atome d'hydrogene a 0,014 eV environ, par suite de la diffusion coherente sur des atomes ayant dps orientations opposees dans la molecule. L'augmentation brusque qui se produit au-dessus de ce seuil correspond a des collisions inelastiques dans lesquelles le spin est inverse: la molecule d'hydrogene est ainsi transformee de la forme para a la forme ortho, absorbant la difference d'energie entre les niveaux fondamentaux de rotation J = 0 et J= 1 des etats ortho et para. Des mesures preliminaires de la perte d'energie neutronique dans les deux domaines d'energie confirment ces interpretations; les experiences se poursuivent en vue d'une etude plus detaillee de la dynamique de l'hydrogene liquide. (author)Abstract (Spanish)
Los autores Comprueban que la seccion eficaz total de dispersion del para-hidrogeno liquido correspondiente a neutrones de energia inferior a 0,014 eV se ajusta aproximadamente a la teoria de Schwinger-Teller relativa al para- hidrogeno gaseoso, lo que indica la intervencion de fuerzas intermoleculares muy debiles. A unos 0,014 eV se alcanza un minimo del orden de 3 b por atomo de hidrogeno, resultante de la dispersion coherente por atomos orientados en direcciones opuestas en la molecula. Al aumentar la energia nertronica por encima de esevalor umbral se observa un incremento brusco que corresponde a lost choques inelasticos en que el espin neutro nico es invertido, con lo que la molecula de para-hidrogeno se convierte en molecula de orto-hidrogeno, absoerbiendo la diferencia de energia existente entre los niveles rotatorios fundamentales J = 0 y J = 1 de los estados para y orto. Las mediciones iniciales de la petdida de energia neutronica en ambas regiones energeticas confirman estas interpretaciones. Dichas mediciones continuan efectuandose con miras a investigar con mas detalle la dinamica de los liquidos. (author)Additional details
Additional titles
- Original title (English)
- Etude de la dynamique de l'hydrogene liquide par la diffusion neutronique; Dinamika zhidkogo vodoroda psh rasseyanii nejtronov.; Estudio de la dinamica del hidrogeno liquido por dispersion neutronica
Publishing Information
- Publisher
- IAEA
- Imprint Place
- Vienna (International Atomic Energy Agency (IAEA))
- Imprint Title
- Inelastic Scattering of Neutrons in Solids and Liquids. V. I. Proceedings of the Symposium on Inelastic Scattering of Neurons in Solids and Liquids
- Imprint Pagination
- 486 p.
- Series
- Proceedings Series
- Journal Page Range
- p. 263-271
- ISSN
- 0074-1884
Conference
- Title
- Symposium on Inelastic Scattering of Neutrons in Solids and Liquids
- Dates
- 10-14 Sep 1962
- Place
- Chalk River (Canada)
INIS
- Country of Publication
- International Atomic Energy Agency (IAEA)
- Country of Input or Organization
- International Atomic Energy Agency (IAEA)
- INIS RN
- 44045042
- Subject category
- S75: CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY;
- Resource subtype / Literary indicator
- Conference
- Descriptors DEI
- CROSS SECTIONS; ENERGY LOSSES; EV RANGE; HYDROGEN; INTERMOLECULAR FORCES; LIQUIDS; NEUTRON DIFFRACTION; NEUTRONS; SPIN
- Descriptors DEC
- ANGULAR MOMENTUM; BARYONS; COHERENT SCATTERING; DIFFRACTION; ELEMENTARY PARTICLES; ELEMENTS; ENERGY RANGE; FERMIONS; FLUIDS; HADRONS; LOSSES; NONMETALS; NUCLEONS; PARTICLE PROPERTIES; SCATTERING
Optional Information
- Notes
- Abstract also available in Russian; 2 figs., 1 tab., 9 refs. Imprint:In two volumes
- Secondary number(s)
- STI/PUB--62(v.1)