The charge transfer (CT) probe ethyl ester of N,N-dimethylamino naphthyl acrylic acid (EDMANA) bound to Human Serum Albumin (HSA) serves as an efficient reporter of the polarity and conformational changes of protein in aqueous buffer (Tris-HCl buffer, pH=7.03) and in presence of denaturant, quencher and reverse micelles. The change in fluorescence intensity and the position of emission maxima of EDMANA in presence of HSA well reflect the nature of binding and location of the probe inside the proteinous environment. The increase in steady state anisotropy values with increase of protein concentration indicate restriction imposed on the mobility of the probe molecules in the proteinous medium. The results of fluorescence quenching of EDMANA by acrylamide, Fluorescence Resonance Energy Transfer (FRET) and Red Edge Excitation Shift (REES) studies throw light on the accessibility to the probe bound to HSA and hence indicate the probable location of the probe within the hydrophobic cavity of HSA. The complicated nature of protein unfolding in presence of urea is well studied by change in the fluorescence properties of EDMANA bound to HSA protein.

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The photodissociation of gaseous benzaldehyde (C(6)H(5)CHO) at 193, 248, and 266 nm using multimass ion imaging and step-scan time-resolved Fourier-transform infrared emission techniques is investigated. We also characterize the potential energies with the CCSD(T)/6-311+G(3df,2p) method and predict the branching ratios for various channels of dissociation. Upon photolysis at 248 and 266 nm, two major channels for formation of HCO and CO, with relative branching of 0.37:0.63 and 0.20:0.80, respectively, are observed. The C(6)H(5)+HCO channel has two components with large and small recoil velocities; the rapid component with average translational energy of approximately 25 kJ mol(-1) dominates. The C(6)H(6)+CO channel has a similar distribution of translational energy for these two components. IR emission from internally excited C(6)H(5)CHO, ν(3) (v=1) of HCO, and levels v≤2, J≤43 of CO are observed; the latter has an average rotational energy of approximately 13 kJ mol(-1) and vibrational energy of approximately 6 kJ mol(-1). Upon photolysis at 193 nm, similar distributions of energy are observed, except that the C(6)H(5)+HCO channel becomes the only major channel with a branching ratio of 0.82±0.10 and an increased proportion of the slow component; IR emission from levels ν(1) (v=1) and ν(3) (v=1 and 2) of HCO and v≤2, J≤43 of CO are observed; the latter has an average energy similar to that observed in photolysis at 248 nm. The observed product yields at different dissociation energies are compared to statistical-theory predicted results based on the computed singlet and triplet potential-energy surfaces.

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