Combined Picosecond Time-Resolved UV-Vis and NMR Techniques Used for Investigation of the Excited State Intramolecular Triplet-Triplet Energy Transfer.

The phenomenon of the intramolecular triplet-triplet (T-T) energy transfer observed for spiro[9,10-dihydro-9-oxoanthracene-10,2'-5',6'-benzindan] () molecule was investigated using stationary and time-resolved techniques in the UV/vis spectral region. The rate constant for energy transfer from anthrone chromophore to the triplet state localized on the naphthalene subunit of molecule is 2.8 × 10 s.

Unveiling the excited state energy transfer pathways in peridinin-chlorophyll a-protein by ultrafast multi-pulse transient absorption spectroscopy.

Time-resolved multi-pulse methods were applied to investigate the excited state dynamics, the interstate couplings, and the excited state energy transfer pathways between the light-harvesting pigments in peridinin-chlorophyll a-protein (PCP). The utilized pump-dump-probe techniques are based on perturbation of the regular PCP energy transfer pathway. The PCP complexes were initially excited with an ultrashort pulse, resonant to the S→S transition of the carotenoid peridinin.

Investigation of the S1/ICT equilibrium in fucoxanthin by ultrafast pump-dump-probe and femtosecond stimulated Raman scattering spectroscopy.

Time-resolved multi-pulse spectroscopic methods-pump-dump-probe (PDP) and femtosecond stimulated Raman spectroscopy-were used to investigate the excited state photodynamics of the carbonyl group containing carotenoid fucoxanthin (FX). PDP experiments show that S1 and ICT states in FX are strongly coupled and that the interstate equilibrium is rapidly (<5 ps) reestablished after one of the interacting states is deliberately depopulated. Femtosecond stimulated Raman scattering experiments indicate that S1 and ICT are vibrationally distinct species.

Optically controlled molecular switching of an indolobenzoxazine-type photochromic compound.

Photochromic forward (oxazine ring-opening) and backward (oxazine ring-closing) switching dynamics of an indolobenzoxazine compound were studied by femtosecond pump-repump-probe technique. A UV pulse was used to excite the ring-closed form of the photochromic compound, causing a C-O bond cleavage and the formation of a spectrally red-shifted isomer within a time scale of ca. 100 ps.