| Project/Area Number |
16072208
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | Kobe University (2006)
Tokyo Institute of Technology (2004-2005) |
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Principal Investigator |
WADA Akihide Kobe University, Molecular Photoscience Research Center, professor (20202418)
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| Co-Investigator(Kenkyū-buntansha) |
KUBOTA Jun University of Tokyo, Department of Chemical System Engineering, Associate Professor (50272711)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥24,700,000 (Direct Cost: ¥24,700,000)
Fiscal Year 2006: ¥7,000,000 (Direct Cost: ¥7,000,000)
Fiscal Year 2005: ¥10,700,000 (Direct Cost: ¥10,700,000)
Fiscal Year 2004: ¥7,000,000 (Direct Cost: ¥7,000,000)
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| Keywords | surface adsorbed molcule / time resolved spectroscopy / excited state dynamics / sum-freauency generation / control of excited state / optimized pulse shaping method / surface reaction / low frequency vibration mode / 振動分光 / 和周波発生法 / 反応制御 / 最適化波形整形 / 超高速分光 / 低派数振動モード |
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| Research Abstract |
The surface dynamics concerned with thermal excitation can be observed by combining rapid temperature rise induced by irradiation of intense near-infrared (NIR) pulse and vibrational sum-frequency generation (SFG) spectroscopy which is surface sensitive and ultrafast spectroscopic technique. In this study, such time-resolved method was applied to methoxy (CH_3O-)/Ni(111) and C_6H_<12>(cyclohexane)/Ni(111) surface systems. On the C_6H_<12>/Ni(111) system, the irradiation with NIR pulses caused a temporary jump in temperature at the Ni(111) surface and enhanced the intensity of the peak from the high-coverage state, but weakened the peaks from the low-coverage state. It was concluded from the results that the temperature jump excites the cyclohexane molecules from the low-coverage state to the high-coverage state. On the (CH_3O-)/Ni(111) system, the observed temporal profile was reproduced by simulation assuming that the original methoxy in the ground state was in chemical equilibrium wi
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th a new state produced by instantaneous heating. It was concluded from the results that a temperature jump of 250 K induced a change in the molecular orientation or adsorption site of methoxy on the Ni(111) surface without decomposition of methoxy to adsorbed CO and hydrogen. On the control of excitation process of molecules, the optimized pulse shaping technique was applied to increase the emission intensity from perylene molecule induced by two-photon excitation using NIR (wavelength of 800 nm) femtosecond pulse. It was found that the pulse-train-like pulse shape with the pulse interval of about 100 fs showed the emission intensity stronger than that by a single femtosecond pulse. The pulse shapes optimized for crystalline and solution samples were very similar to each other, and the pulse shape effective for the crystalline sample was also effective for the solution sample and vice versa. It was concluded that the mechanism for the efficiency increase was essentially the same for the crystalline and solution samples, and that the intramolecular vibrational modes at around 330 cm^<-1> (oscillation period of about 100 fs) were deeply involved in the excitation process. Less
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