| Abstract [eng] |
The thesis explores ultrafast electronic and vibrational dynamics of several naturally occurring photosynthetic pigments, such as carotenoids β-carotene and fucoxanthin, in addition to various synthetic indolo[2,1-b][1,3]benzoxazine-type photochromic compounds. The complex sub-nanosecond spectral dynamics of these molecular systems are explored by multi-pulse ultrafast transient absorption methods. Pump-dump-probe (PDP) and pump-repump-probe (PrPP) spectroscopic techniques are applied to perturb the regular photoevolution of the investigated molecular species, thus gaining additional information on the excited state behavior, branching evolutionary pathways, and the interaction between the transient species. Moreover these methods showcase the ability to directly control these photoreactions with a properly-timed femtosecond pulse sequence. Additionally, a significant portion of the thesis is dedicated to design, assembly, and practical implementation of a multi-pulse femtosecond stimulated Raman scattering (FSRS) spectroscopic setup. FSRS techniques are employed to explore the ultrafast structural evolution of the examined photochromic and photosynthetic systems. Since FSRS can be fine-tuned to enhance a particular electronic resonance, these techniques allow us to gain a better understanding of the vibronic properties (and the possible coupling channels) of the involved excited states. |
