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Structures and Dynamics of Charge-Separated Excited States Studied by Picosecond Infrared Spectroscopy

Research Project

Project/Area Number 11440171
Research Category

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

Allocation TypeSingle-year Grants
Section一般
Research Field Physical chemistry
Research InstitutionOkazaki National Research Institutes (2000)
The University of Tokyo (1999)

Principal Investigator

OKAMOTO Hiromi  Okazaki National Research Institute, Institute for Molecular Science, Professor, 分子科学研究所, 教授 (20185482)

Project Period (FY) 1999 – 2000
Project Status Completed (Fiscal Year 2000)
Budget Amount *help
¥9,200,000 (Direct Cost: ¥9,200,000)
Fiscal Year 2000: ¥2,300,000 (Direct Cost: ¥2,300,000)
Fiscal Year 1999: ¥6,900,000 (Direct Cost: ¥6,900,000)
KeywordsUltrafast Spectroscopy / Transient Infrared Spectroscopy / Electronically Excited / Charge Transfer / Picosecond / Molecular Structure / (Dimethylamino) benzonitrile
Research Abstract

In this project, we have first tried to improve the sensitivity of the time-resolved infrared system, and then we have measured transient infrared spectra of molecules described in the following, and have discussed molecular and electronic structures of the excited species. As hydrocarbon molecules with symmetric structures, we have studied on trans-stilbene and diphenylacetylene in polar and non-polar solvents. As"push-pull"molecules with electron donating (ex. amino or pyrrolyl) and accepting (ex. cyano) groups linked by conjugated pi-electron systems (benzene rings), we have studied on (dimethylamino)benzonitrile (DMABN), cyanobenzquinuclidine (CBQ), and (cyanophenyl)pyrrole (CPP). On molecules of this type, characteristic structures of charge-transfer (CT) excited states in polar environments, with the amino or pyrrolyl groups twisted perpendicularly to the benzene ring plane, have been discussed. However, experimental evidence for the structure is scant and this problem is still a matter of controversy among researchers. In the present study, we have measured picosecond infrared spectra of CT and locally excited (LE) states of DMABN and the isotope-substituted species, and have discussed on the CT molecular structure based on the reliable vibrational assignments, as well as from the comparison with CBQ and CPP as molecules with related structures. We have succeeded in establishing vibrational assignments of infrared bands of the CT state of DMABN, and have revealed that the electronic structure of the CT state contains both quinoidal and benzenoidal contributions. However, in the present stage, we do not have the final conclusion (planar or twisted) about the molecular structure, unfortunately.

Report

(3 results)
  • 2000 Annual Research Report   Final Research Report Summary
  • 1999 Annual Research Report
  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] Hiromi Okamoto: "Picosecond infrared spectroscopy of electronically excited trans-stilbene in solution in the fingerprint region"Journal of Physical Chemistry A. 103. 5852-5857 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Hiromi Okamoto: "Picosecond transient infrared spectrum of 4-(dimethylamino) benzonitrile in the fingerprint region"Journal of Physical Chemistry A. 104. 4182-4187 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Takaaki Ishibashi: "Picosecond transient infrared spectra and structure of S1 diphenylacetylene in solution"Chemical Physics Letters. 325. 212-218 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Hiromi Okamoto: "Infrared and Raman spectra of 4-(dimethylamino) benzonitrile and isotopomers in the ground state and vibrational analysis"Chemical Physics. 260. 193-214 (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Hiromi Okamoto: "Picosecond infrared spectra of isotope-substituted 4-(dimethylamino) benzonitriles and molecular structure of the charge-transfer singlet excited state"Journal of Physical Chemistry A. (印刷中).

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] H.Okamoto: "Picosecond infrared spectroscopy of electronically excited trans-stilbene in solution in the fingerprint region"J.Phys.Chem.A. 103. 5852-5857 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] H.Okamoto: "Picosecond transient infrared spectrum of 4-(dimethylamino) benzonitrile in the fingerprint region."J.Phys.Chem.A. 104. 4182-4187 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] T.Ishibashi, H.Okamoto, H.Hamaguchi: "Picosecond transient infrared spectra and structure of S1 diphenylacetylene in solution."Chem.Phys.Lett.. 325. 212-218 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] H.Okamoto, H.Inishi, Y.Nakamura, S.Kohtani, R.Nakagaki: "Infrared and Raman spectra of 4-(dimethylamino) benzonitrile and isotopomers in the ground state and vibrational analysis."Chem.Phys.. 260. 193-214 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] H.Okamoto, H.Inishi, Y.Nakmura, S.Kohtani, R.Nakagaki: "Picosecond infrared spectra of isotope-substituted 4-(dimethylamino benzonitriles and molecular structure of the charge-transfer singlet excited state."J.Phys.Chem.A. in press.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2000 Final Research Report Summary
  • [Publications] Hiromi Okamoto: "Picosecond Transient Infrared Spectrum of 4-(Dimethylamino) benzonitrile in the Fingerprint Region"The Journal of Physical Chemistry A. 104・18. 4182-4187 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Taka-aki Ishibashi: "Picosecond transient infrared spectra and structure of S_1 diphenylacetylene in solution"Chemical Physics Letters. 325. 212-218 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Hiromi Okamoto: "Infrared and Raman spectra of 4-(dimethylamino) benzonitrile and isotopomers in the ground state and vibrational analvsis"Chemical Physics. 260. 193-214 (2000)

    • Related Report
      2000 Annual Research Report
  • [Publications] Hiromi Okamoto: "Picosecond infrared spectra of isotope-substituted 4-(dimethylamino) benzonitriles and molecular structure of the charge-transfer singlet excited state"The Journal of Physical Chemistry A. (印刷中).

    • Related Report
      2000 Annual Research Report
  • [Publications] Hiromi Okamoto: "Picosecond Transient Infrared Spectrum of 4-(Dimethylamino) benzonitrile in the Fingerprint Region"TheJournal of Physical Chemistry A. (印刷中).

    • Related Report
      1999 Annual Research Report

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Published: 1999-04-01   Modified: 2016-04-21  

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