1998 Fiscal Year Final Research Report Summary
Photophysical and photochemical processes of several aramatic molecules
| Project/Area Number |
09640599
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Physical chemistry
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
HIKIDA Takumi Guraduate School of Science and Engineering, TOKYO INSTITUTE OF TECHNOLOGY,Professor, 大学院・理工学研究科, 教授 (60016144)
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| Project Period (FY) |
1997 – 1998
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| Keywords | supercritical fluid / aromatic molecule / phosphorescence guantum field / lifetime / excimer / dimer |
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| Research Abstract |
Photophysical and photochemical processes of several aromatic molecules were studied in supercritical fluids by means of time-resolved and steady- state measurements.
The emission intensity decay curve of pyrene in the CO_2 supercritical fluid showed a 12 ns rise and a 100 ns decay. The former is that of the excimer lifetime, while the later is the lifetime of excited pyrene. The monomer fluorescence intensity was proportional to the concentrations of pyrene while that of excimer emission was nearly constant regardless of the concentrations.
Absorption spectra of tetracene in the CO_2 supercritical fluid showed a new absorption band at around 525 nm which was assigned to that of the ground state dimer. The emission intensity decay measured at 550 nm were analyzed in terms of biexponential function, 12 ns and 22 ns. The lifetime of 12-13 ns is those of monomer and 22 ns is the dimer lifetime.
The emission spectra of Cl-naphthalene in the CO_2 supercritical fluid consisted of the weak phosphorescence emission at around 430-600 nm as well as the ordinary monomer fluorescence appearing at around 300-400 nm. The fluorescence quantum yield was about 0.5 while that of the phosphorescence was about 10^<-5>. The emission intensity decay measured at 350 nm was 5 ns, while that measured at 500 nm was about 100 ns.
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