2004 Fiscal Year Final Research Report Summary
Studies on Molecular Structure and Dynamics by Doppler-free High-resolution Laser Spectroscopy
| Project/Area Number |
15350014
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Kobe University |
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Principal Investigator |
KATO Hajime Kobe University, Molecular Photoscience Research Center, Professor, 分子フォトサイエンス研究センター, 教授 (60030780)
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| Co-Investigator(Kenkyū-buntansha) |
KASAHARA Shunji Kobe University, Molecular Photoscience Research Center, Associate Professor, 分子フォトサイエンス研究センター, 助教授 (00260646)
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| Project Period (FY) |
2003 – 2004
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| Keywords | Doppler-free / Glyoxal / Benzene / Naphthalene / dibenzo-p-dioxin / Radiationless transition / Laser / Magnetic field |
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| Research Abstract |
1.Doppler-free two-photon fluorescence excitation spectra of the A^1A_u(v_7=1)←X^1A_g transition of trans-glyoxal were measured under the magnetic field up to 6T. By analyzing the results, it is concluded that the Zeeman splitting of the A^1^A_u state is originating from the mixing of the 1^3Bu state by spin-orbit interaction and the magnetic moment is along the top axis.
2.High resolution excitation spectra and the Zeeman effects for the low-lying vibrational band of the S_1^1B_<2u>←S_0^1A_<1g> transition in gaseous benzene-d_6 were measured. No perturbation originating from an interaction with a triplet state was observed in both bands. It became clear from the Zeeman spectra that rotationally resolved levels are not mixed with a triplet state. Accordingly, it was concluded that the intersystem mixing is not likely to occur at levels of low excess energy in the S_1 state of an isolated benzene.
3.Doppler-free two-photon excitation spectrum and the Zeeman effect of the S_1^1B_<1u>(v_<21>=1)←S_0^1A_g(v=0) transition of naphthalene have been measured. Rotationally resolved levels were found not to be mixed with a triplet state from the Zeeman spectra. It is demonstrated that nonradiative decay of an isolated naphthalene excited to low rovibronic levels in the S_1 state does not occur through the intersystem mixing. 188
4.Sub-Doppler high-resolution excitation spectra of dibenzo-p-dioxin (DD) have been observed for the 0_0^0 and 0_0^0+22 cm^<-1> bands of the S_1←S_0 transition by crossing a tunable laser beam perpendicular to a collimated molecular beam. The observed spectra were reproduced well by simulating the spectra as the a-type transition, and the S_1 state is identified to be a ^1B_<1u> state. The DD molecule has been shown t 0_0^+22 cm^<-1> band is assigned as a transition to the a_g component of butterfly mode.
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