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Excited-state proton transfer (ESPT) from pyranine (8-hydroxypyrene-1,3,6-trisulfonate, HPTS) to acetate was studied in [gamma]-cyclodextrin ([gamma]-CD) and 2-hydroxypropyl-[gamma]-cyclodextrin (HP-[gamma]-CD). It was found that, in both the cyclodextrins, ESPT from HPTS to acetate was much slower than in bulk water and ESPT of HPTS in substituted [gamma]-cyclodextrin was slower than that in the unsubstituted one.

Two compact denatured states of glutaminyl-tRNA synthetase (GInRS) under equilibrium conditions in the presence of a naturally occurring osmolyte, L-glutamate are characterized. Dynamic light scattering studies reveal that both the compact denatured states are aggregated under the measurement conditions.

Fluorescence anisotropy decay and solvation dynamics of coumarin 153 (C153) are studied in dimethyl beta-cyclodextrin (DIMEB) and trimethyl beta-cyclodextrin (TRIMEB) nanocavity in water. Solvation dynamics of C153 in DIMEB exhibits a very fast (2.4 ps) component (41%) and two slower components of 50 ps (29%) and 1450 ps (30%).

Solvation dynamics of coumarin 480 (C480) is studied in a nanoporous sol-gel matrix. Its effect in the presence of cetyltrimethylammonium bromide is studied.

Femtosecond emission spectroscopy is used for studying excited-state proton transfer (ESPT) of pyranine (8-hydroxypyrene-1,3,6-trisulfonate, HPTA) in a polymer-surfactant aggregate. The polymer-surfactant aggregate is a supramolecular assembly that has a triblock copolymer [(PEO).sub.20]-[(PPO).sub.70]-[(PEO).sub.20] (P123) and a cationic surfactant, cetyltrimethylammonium chloride (CTAC).

Femtosecond upconversion is used to study the excitation wavelength dependence of the solvation dynamics of coumarin 480 (C480) in a triblock copolymer [(PEO).sub.20]-[(PPO).sub.70]-[(PEO).sub.20] (P123)-sodium dodecyl sulfate (SDS) aggregate. The magnitude of the [[lambda].sub.ex] dependence in P123-SDS is shown to be much smaller than that of P123 micelle, thus providing better insights on the difference between the properties of the core and the corona region than static absorption and emission spectra.

Photoinduced electron transfer (PET) from N,N-dimethylaniline (DMA) to four coumarin dyes inside the cavity of hydroxypropyl gamma-cyclodextrin (hpCD) is explored using femtosecond upconversion. Results indicate that inside the nanocavity of hpCD, photoinduced PET from DMA to coumarin dyes exhibits a component in a few picosecond time scales.

Study is conducted using femtosecond time-resolved fluorescence spectroscopy, to show that the solvation dynamics in the two partially folded states (I(sub s)(super ') and I(sub s)(super '') of a protein, cytochrome C, are very different. Solvation dynamics of I(sub s)(super '') displays a major component of 1.3 ps which indicates that the structure of I(sub s)(super '') is much more open and exposed compared to that of I(sub s)(super ').

Effect of temperature on the fluorescence anisotropy decay and the ultraslow component of solvation dynamics of coumarin 153 (C153) in a gamma-cyclodextrin (gamma-CD) nanocavity are studied using a picosecond set up. The ultraslow component and the temperature dependence of solvation dynamics are attributed to a dynamic exchange between free and bound water molecules.

Solvation dynamics at the active site of an enzyme, glutaminyl-tRNA synthetase are studied using a fluorescence probe, acrylodan, site-specifically attached at cysteine residue C229, near the active site. The picosecond time-dependent fluorescence Stokes shift indicates slow solvation dynamics at the active site of the enzyme in the absence of any substrate.