| Project/Area Number |
13640518
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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 | Waseda University |
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Principal Investigator |
TSUCHIYA Soji Waseda University, Advanced Research Institute for Science and Engineering, Professor, 理工学総合研究センター, 教授 (40012322)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAKITA Nami Faculty of Science, Japan Women's Univ., Assistant, 理学部, 助手 (90277674)
OBI Kinichi Faculty of Science, Japan Women's Univ., Professor, 理学部, 教授 (10016090)
TAKAHASHI Hiroaki Waseda Unviersity, School of Science and Engineering, Professor, 理工学部, 教授 (40063622)
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| Project Period (FY) |
2001 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 2002: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2001: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Vibronic State / Acetylene / Anharmonic coupling / Photodissociation / Predissociation / 前期解離 |
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| Research Abstract |
Vibrational and reaction dynamics of electronic excited acetylene have been investigated.
1. The vibrational level structure of acetylene in the electronic excited A^^〜 state was believed to be the progressions of the 2^n3^m vibrational states. However, in this work it was proved that the V_3' mode couples anharmonically with the ungerade v_4'/v_6' mode to form a polyad structure composed of the 2^m3^n, 2^m3^<n-1>(4/5)^2, 2^m3^<n-2>(4/6)^4, ………. The same type of the anharmonic coupling was found for the ungerade vibrational states which were investigated by an IR-UV double resonance spectroscopy. In this case, the (4/6) states having odd quantum numbers couple with the 3^n state.
2. The predissociation rate constants of acetylene in respective rovibronic levels of the A^^〜 state were determined through observation of the spectral line-widths. The rate constants were found to be independent of the vibrational parity gerade or ungerade. This can be attributed to the anharmonic coupliig between the V_3' and V_4'/V_6' modes which causes the gerade and ungerade states to have a similar vibrational chracteristics.
3. It was found that the triplet state-mediated predissociation of excited acetylene toward C_2H(X^^〜)+H ceases around the excitation energy of 51100 cm^<-1> which is far beyond the adiabatic dissociation threshold of the A state. At this energy, acetylene still predissociates at a rate of around 10^<10> s^<-1> to form C_2H(A^^〜) + H.
4. A new experimental technique, Differential Temperature Laser Induced Fluorescence Spectroscopy, was developed which is capable of separating overlapping cold and hot bands of a LIF spectrum.
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