Study Aggregation of Chlorophyll a In Non-polar Solvents and Vibrational Dynamics of Cyanine Dye HDITCP Solution

• Main Authors: Chang, Ming-Shien, 張銘顯
• Other Authors: F. G. Yee, S. H. Lin
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/62790284282365658527

碩士 === 國立臺灣大學 === 物理學系 === 85 === In the first part of this thesis, the absorption spectra of Chlorophyll a (Chl a) in non-polar solvents are taken for the study of aggregation of Chl a. Concentration- and time-dependent experiments are performed on several polar and non-polar solvents. The Gibbs free energy of dimerization of Chl a are calculated. Some discussion for the unwelcome hydration are also given at the end of this part. Femtosecond laser sources are powerful tools for the study of ultra-fastphenomena on picosecond and sub-picosecond time scales. Thus it can be used to study the vibrational motions and their relaxation mechanisms, both dephasing and relaxation, of polyatomic molecules. Therefore, in the second part, we use a ultra-fast laser source to study the vibrational motions and the relative phenomena of a cyanine dye HDITCP solution. A Ti:sapphire femtosecond pulse laser is used to excite and probe HDITCPdye molecules. Incorporating with an optical delay line and Lock-In technique, we build a pump-probe measurements setup in our laboratory. Then we execute a series of wavelength-dependent one-color-pump-probe measurements from 780---860 nm. The vibration motions and their dephasing are observed in these experiments. The possible mechanisms governing this phenomena are alsodeduced. Finally, conclusion and future studies on these two experiments are proposed at the end of this thesis.