• Search Research Projects
  • Search Researchers
  • How to Use
  1. Back to previous page

Electron-densitiy distributions in transition-metal compounds-Observation by short wave-length SR.

Research Project

Project/Area Number 02044051
Research Category

Grant-in-Aid for international Scientific Research

Allocation TypeSingle-year Grants
SectionJoint Research
Research InstitutionTokyo Institute of Technology

Principal Investigator

MARUMO Fumiyuki  Tokyo Institute of Technology, 工業材料研究所, 教授 (10013492)

Co-Investigator(Kenkyū-buntansha) SPADACCINI Nick  University of Western Australia, 結晶学センター, 講師
HALL S.R.  西オーストラリア大学, 結晶学センター, 助教授
MASLEN E.N.  西オーストラリア大学, 結晶学センター, 教授
ISHIZAWA Nobuo  Tokyo Institute of Technology, 工業材料研究所, 助教授 (90151365)
ITO Tetsuzo  Kanagawa Institute of Technology, 工学部, 教授 (60087400)
OHSUMI Kazumasa  Laboratory for High Energy Physics, 放射光実験施設, 助教授 (70011715)
SATOW Yoshinori  University of Tokyo, 薬学部, 教授 (30150014)
HALL Sydney R.  University of Western Australia
MASALEN Edward N.  University of Western Australia
Project Period (FY) 1990 – 1991
Project Status Completed (Fiscal Year 1991)
Budget Amount *help
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 1991: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1990: ¥2,000,000 (Direct Cost: ¥2,000,000)
KeywordsElectron-Density Distribution / Transition Metal Compounds / Short Wavelength / Synchrotron Radiation / Extinction Correction / Perovskite-type Compounds / 単結晶構造解析 / 積分強度 / X線回折 / 放射光 / ペロブスカイト型構造 / 温度因子 / 超伝導
Research Abstract

This project has been undertaken as an international joint program between Japanese and Australian crystallographers for the purpose of solving various experimental problems posed on an attempt to develop the X-ray diffraction technique to an promising analytical method for precise electron-distribution analysis in crystals. The primary concern was on establishment of a technique to remove the secondary extinction effects on the integrated intensities of X-rays diffracted from crystals by making use of short wavelength synchrotron radiations (SR). The obtained results can be summarized as follows :
Integrated intensities of a spherically-shaped FeTiO_3 crystal with diameter of 145mum have been collected on a horizontal-type four circle diffractomator at the beam line 14A in the Photon Factory of the National Laboratory for High Energy Physics, Japan. Synchrotron radiations, emitted from the vertical wiggler and monochromatized to 0.34965(5) and 0.41996(14)* using an Si double-crystal mo … More nochromator, were employed for the data collection. Similar measurements were also carried out on the same crystal using AgKalpha (0.56087, *) and MoKalpha (0.71073*) radiations. The effect of secondary extinction on the diffraction data has been examined using these data sets taken with the four different wavelengths. It was revealed that the difference between the observed structure factors before and after the extinction correction was less than 4% at maximum in the 0.35* SR data, indicating that the extinction correction might be practically negligible for the data collected with X-rays of wavelength shorter than 0.3*. In the overall accuracy, however, the 0.35, * SR data were worse those taken with Mo Kalpha radiation because of the instability of the incident SR beam and enlarged errors in counting statistics of the diffracted beams due to the low fraction of the incident beam. The instability is supposed to be mainly caused by a steep drop of intensity against shortening of the wavelength in the case of SR emitted from the vertical wiggler in the wavelength region shorter than around 0.5*. In conclusion, it was suggested to use smaller crystals in combination with a strong and stable SR having a wavelength between 0.5 and 0.9* in place of a SR with a short wavelength such as 0.35* in order to avoid secondary extinction effects. Successful results have been obtained on crystals of K_2SiF_6 and KZnF_3 with dimensions of about 30mum in diameter, utilizing 0.7* SR. In addition, precise analyses of SR data from small crystals of KCuF_3, SrTiO_3, BaTiO_3 and La_<1.88>Sr_<0.12>CuO_4, which were obtained in almost extinction-free conditions, are now in progress and expected to give fruitful. results with respect to their electron-density distributions. Less

Report

(2 results)
  • 1991 Final Research Report Summary
  • 1990 Annual Research Report
  • Research Products

    (6 results)

All Other

All Publications (6 results)

  • [Publications] M.Ohgaki,F.Marumo and K.Tanaka: "Integrated Intensities Collected with Short Wavelength X-Rays and Extinction Effects" Report of the Research Laboratory of Engineering Materials. (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] T.Ito,F.Marumo,T.Maslen,Y.Satw and K.Tanaka: "Accurate Diffraction Seudies of Perovskite Structures at Two Wevelength" Photon Factory Activity Report. 8. 282 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] M. Ohgaki, F. Marumo and K. Tanaka: "Integrated Intensities Collected with short Wavelength Xrays and Extinction Effects" Report of the Research Laboratory of Engineering Materials. (1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] T. Ito, F. Marumo, T. Maslen, Y. Satow and K. Tanaka: "Accurate Diffraction Studies of Perovskite Structures at Two Wavelength" Photon Factory Activity Report. 8. 282 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] N.Spadaccini,E.N.Maslen: "The Electron Density Distribution in KZnF_3 From Xーray Diffraction Data Collected at 0.5 and 0.7A" Acta Crystallographica.

    • Related Report
      1990 Annual Research Report
  • [Publications] M.Ohgaki,F.Marumo K.Tanaka: "Extinction Effect in Integrated Intensities Collected with Short Wavelength Xーrays" Mineralogical Journal.

    • Related Report
      1990 Annual Research Report

URL: 

Published: 1990-04-01   Modified: 2016-04-21  

Information User Guide FAQ News Terms of Use Attribution of KAKENHI

Powered by NII kakenhi