Project/Area Number  08640657 
Research Category 
GrantinAid for Scientific Research (C)

Section  一般 
Research Field 
Physical chemistry

Research Institution  Okazaki National Resarch Institute 
Principal Investigator 
TANIMURA Yoshitaka Okazaki National Resarch Institute, Institute for Molecular Science, 分子科学研究所, 助教授 (20270465)

CoInvestigator(Kenkyūbuntansha) 
OKUMURA Ko Okazaki National Resarch Institute, Institute for Molecular Science, Institute f, 分子科学研究所, 助手 (80271500)

Project Fiscal Year 
1996 – 1997

Project Status 
Completed(Fiscal Year 1997)

Budget Amount *help 
¥1,000,000 (Direct Cost : ¥1,000,000)
Fiscal Year 1997 : ¥1,000,000 (Direct Cost : ¥1,000,000)

Keywords  2D Raman / Path Integral / FokkerPlanck / Femtosecond / nonlinear optics / Brownian / 2次元ラマン分光 / 5次光学過程 / 量子ブラウン運動 / CS2 / フォッカー・プランク方程式 / モスポテンシャル系 / 非調和振動子 / 経路積分 / CS_2 
Research Abstract 
The nonlinear optical response of a molecular system in the condensed phase subjected to a series of offresonant femtosecond laser pulses has been studied to investigate inhomogeneous broadening of liquid states and anharmonicity of vibrational modes. We have derived analytical expressions of the 5th order response function for an anharmonic system using pathintegral techniques. Applying this equation, we have studied the interplay between anharmonicity and inhomogeneity. The fifthorder response function for a displaced anharmonic system has been also derived and applied to study photon echo, pumpprobe experiments and newly developed the fifthorder experiment which is designed to detect weak anharmonicity of potentials. Using a quantum FokkerPlanck equation, we have studied higherorder optical processes of Morse potential systems. This FokkerPlanck equation can treat a molecular system with any shape of potential coupled to a Gaussianwhite or a Gaussian Markovian noisebath. We
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have presented a procedure to calculate the thirdand fifthorder response functions, which are equivalent to the secondand thirdorder correlation functions of the molecular coordinate, by way of the eq. of motion approach. Assuming the potential surface of a Cesium dimer, which is modeled by the Morse potential, and the linear and nonlinear coordinate dependence of the polarizability, we calculated the thirdand fifthorder response functions for various temperatures and heatbath couplings. By plotting two timeevolution period involved in the fifthorder spectroscopy, we obtained the twodimensional profiles of the signals. These 2D profiles are sensitive for a shape of potential and polarizability, even for a strong damping case, and depend on the temperature. This indicates that fifthorder twodimensional spectroscopy carried out for a different temperature allows us to access information of the potential and the polarizability. We have also presented the FokkerPlanck equation for multistate systems and applied to the displaced Morse oscillators system. Optical Stark effects of it was observed and discussed. Less
