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Heat Capacity at Constant Volume and Molecular Motion of Crystal, Orientationally Disordered Crystal and Liquid

Research Project

Project/Area Number 02453008
Research Category

Grant-in-Aid for General Scientific Research (B)

Allocation TypeSingle-year Grants
Research Field 物理化学一般
Research InstitutionTokyo Institute of Technology

Principal Investigator

OGUNI Masaharu  Tokyo Institute of Technology, Faculty of Science Department of Chemistry, Associate Professor, 理学部, 助教授 (50144423)

Project Period (FY) 1990 – 1991
Project Status Completed (Fiscal Year 1991)
Budget Amount *help
¥7,200,000 (Direct Cost: ¥7,200,000)
Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1990: ¥5,800,000 (Direct Cost: ¥5,800,000)
KeywordsHigh pressure calorimeter / Heat capacity / Phase transition / Glass transition / Orientationally disordered crystal / Coupling / Molecular motion / 高圧熱容量 / 配向無秩序 / 無秩序結晶
Research Abstract

The present research aimed at making progress in the thermodynamic understanding on the coupling effects between orientational degrees of freedom and between them and the other degrees of freedom in orientationally disordered crystals.
1) Effort was made to construct an automatic high-pressure calorimeter which measures simultaneously both heat capacity and volume at constant pressure to allow one to derive heat capacity at constant volume later from. The calorimeter is workable in the temperature range of 13 K to 500 K and enables high-precision thermometry of 10^<-5> K and heat capacity measurement with inaccuracy around 1 % at high pressures. We have so far succeeded in maintaining high pressure up to 200 MPa with its imprecision of 1 kPa within the high-pressure system. The remaining problem to be solved is in preparation of a thin sample-ampoule of indium which separates the sample and high pressure medium within the calorimeter cell.
2) Orientationally disordered crystals, 2-haloge … More nothiophenes and pyridinium salts, were studied through heat capacity measurements under atmosphere. In the former crystals, glass transitions of one step and of two steps were observed in 2-bromothiophene and 2-chlorothiophene, respectively, and their properties changed continuously with a variation of composition between the two substances. These indicate that two reorientational processes couple with each other in both the dynamic and thermodynamic properties. In the latter cystals, pyridium iodide exhibited one phase transition while the chloride two phase transitions leading to the same high-temperature states in their orientational degrees of freedom. In pyridinium hexafluorophosphate, orientational disorderings of the cation and anion proceeded under strong coupling with each other showing only one phase transition as in the iodide. These suggest that the coupling effects stated above play quite important role in the evolution of orientational disordering both in the static and dynamic aspects. Less

Report

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

    (9 results)

All Other

All Publications (9 results)

  • [Publications] Fujimori,Hiroki: "Construction of an Adiabatic Calorimeter at Low Temperatures and Glass Transition of Crystalline 2-Bromothiophene" Journal of Physics and Chemistry of Solids.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Fujimori,Hiroki: "Enthalpy Relaxation Phenomena in the Glass Transitions of Two Correlated Modes of Reorientation in Crystalline 2-Chlorothiophene" Jounal of Chemical Physics.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Hanaya,Minoru: "Calorimetric Study of Phase Transitions in Pyridinium Iodide and Pyridinium Hexafluorophosphate Crystals" Jounal of Physics and Chemistry of Solids.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Fujimori, Hiroki and Oguni, Masaharu: "Construction of an Adiabatic Calorimeter at Low Temperatures and Glass Transition of Crystalline 2-Bromothiophene" J. Phys. Chem. Solids.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Fujimori, Hiroki and Oguni, Masaharu: "Enthalpy Relaxation Phenomena in the Glass Transitions of Two Correlated Modes of Reorientation in Crystalline 2-Chlorothiophene" J. Chem. Phys.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Hanaya, Minoru, Ohta, Naoki and Oguni, Masaharu: "Calorimetric Study of Phase Transitions in Pyridinium Iodide and Pyridinium Hexafluorophosphate Crystals" J. Phys. Chem. Solids.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Fujimori,Hiroki: "Construction of an Adiabatic Calorimeter at Low Temperatures and Glass Transition of Crystalline 2ーBromothiophene" Journal of Physics and Chemistry of Solids.

    • Related Report
      1991 Annual Research Report
  • [Publications] Fujimori,Hiroki: "Enthalpy Relaxation Phenomena in the Glass Transitions of Two Correlated Modes of Reorientation in Crystalline 2ーChlorothiophene" Jounal of Chemical Physics.

    • Related Report
      1991 Annual Research Report
  • [Publications] Hanaya,Minoru: "Calorimetric Study of Phase Transitions in Pyridinium Iodide and Pyridinium Hexafluorophosphate Crystals" Jounal of Physics and Chemistry of Solids.

    • Related Report
      1991 Annual Research Report

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

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