11:30 AM - 11:45 AM
[17a-418-10] Time-resolved observation of isomerization using two-dimensional transient absorption spectrometer with white light excitation
Keywords:isomerization, Fourier transform, white light
In a photochemical reaction, multicolor multistep photoreaction pathways would exist in parallel to the one photon reaction pathway recognized as a main reaction pathway. For understanding these various reaction pathways, white light irradiation is effective because white light can induce various sequential photoreaction. In this point of view, we developed Fourier transform two-dimensional (2D) transient absorption spectrometer (FT-2DTAS), which uses white light covering entire visible wavelength region for pump and probe light. In this system, white pump light is passed through the Fabry-Pérot interferometer to modulate the white light at different frequency for each wavelength. By using this method, photoinduced events can be assigned to the wavelength of concerned light. In the previous study, we succeeded to observe multicolor multistep photoreaction pathways in the isomerization of azobenzene derivatives. However, it was difficult in the system to observe thermally unstable transient species (τ<ms) due to the use of cw pump and probe light. In order to overcome this problem, flash lamps with pulse width of a few microseconds were introduced for FT-2DTAS as pump and probe white light. Using the improved system, we succeeded to measure microsecond time-resolved 2D transient spectra of isomerization of azobenzene derivatives.