Community Research and Development Information Service - CORDIS

Abstract

Neutron experiments have been performed to measure the induced spin density distribution in single crystals of uranium tetrachloride at low temperature. A structural refinement has also established the atomic positions and thermal parameters at low temperature and these are in agreement with earlier studies. The spin density distribution, determined with polarized neutrons, shows small but significant deviations from that expected from the single ion crystal field model. Fourier difference maps show a small depletion of the (5f) density near the U site and a small positive increase about 1 ANGSTROEM from the U site and principally along the shorter U-C1 bonds. We ascribe this to population of a 6d(x**2 - y**2) orbital. No significant spin density is associated with the C1 site. Model calculations are presented which qualitatively account for the observed effect and involve electron transfer from the 5f to the 6d antibonding orbital formed as a result of a covalent interaction between the U 6d and C1 p states. This is the first direct observation of covalency in systems involving 5f 6d electrons.

Additional information

Authors: LANDER G H, INST. LAUE LANGEVIN, GRENOBLE (FRANCE);ARGONNE NAT. LAB. (USA);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS;KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMANY);SPIRLET M R, INST. LAUE LANGEVIN, GRENOBLE (FRANCE);ARGONNE NAT. LAB. (USA);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS;KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMANY);BROWN P J, INST. LAUE LANGEVIN, GRENOBLE (FRANCE);ARGONNE NAT. LAB. (USA);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS;KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMANY);REBIZANT J, INST. LAUE LANGEVIN, GRENOBLE (FRANCE);ARGONNE NAT. LAB. (USA);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS;KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMANY);KANELLAKOPULOS B, INST. LAUE LANGEVIN, GRENOBLE (FRANCE);ARGONNE NAT. LAB. (USA);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS;KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMANY);KLENZE R INST. LAUE LANGEVIN, GRENOBLE (FRANCE), INST. LAUE LANGEVIN, GRENOBLE (FRANCE);ARGONNE NAT. LAB. (USA);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS;KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMANY);ARGONNE NAT. LAB. (USA), INST. LAUE LANGEVIN, GRENOBLE (FRANCE);ARGONNE NAT. LAB. (USA);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS;KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMANY);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM), INST. LAUE LANGEVIN, GRENOBLE (FRANCE);ARGONNE NAT. LAB. (USA);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS;KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMANY);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS, INST. LAUE LANGEVIN, GRENOBLE (FRANCE);ARGONNE NAT. LAB. (USA);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS;KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMANY);KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMAN, INST. LAUE LANGEVIN, GRENOBLE (FRANCE);ARGONNE NAT. LAB. (USA);UNIV. DE LIEGE AU SART-TILMAN (BELGIUM);EUROPEAN INST. FOR TRANSURANIUM ELEMENTS;KERNFORSCHUNGSZENTRUM, KARLSRUHE (GERMANY)
Bibliographic Reference: J CHEM. PHYS., VOL. 83 (1985), NO. 11, PP. 5988-5997.
Record Number: 1989124090500 / Last updated on: 1987-01-01
Category: PUBLICATION
Available languages: en