Fluorescent proteins exhibit interesting excited state photochemistry, leading to bright fluorescence emission that renders their versatile biological role and wide use as biomarkers. A molecular-level mechanism of the excited state dynamics is desirable to pinpoint the origin of the bright fluorescence of these proteins. Here we present studies on a yellow fluorescent protein variant, Venus, and investigate the photophysics behind the dual fluorescence emission upon UV excitation. Based on our studies, we propose that the unique nature of the potential energy surface is responsible for the observation of minor fluorescence in Venus which is not seen in wild type GFP.

The usefulness of a chirped broadband probe and spectral dispersion to obtain Raman spectra under nonresonant/resonant impulsive excitation is revisited. A general methodology is presented that inherently takes care of phasing the time-domain low-frequency oscillations without probe pulse compression and retrieves the absolute phase of the oscillations. As test beds, neat solvents (CCl4, CHCl3, and CH2Cl2) are used. Observation of periodic intensity modulation along detection wavelengths for particular modes is explained using a simple electric field interaction picture. This method is extended to diatomic molecule (iodine) and polyatomic molecules (Nile blue and methylene blue) to assign vibrational frequencies in ground/excited electronic state that are supported by density functional theory calculations. A comparison between frequency-domain and time-domain counterparts, i.e., stimulated Raman scattering and impulsive stimulated Raman scattering using degenerate pump–probe pairs is presented, and most importantly, it is shown how impulsive stimulated Raman scattering using chirped broadband probe retains unique advantages offered by both.

Planar carbazole based hexaphyrin-like macrocycles with bis-coordinating cores and box-shaped cyclic BODIPYs were synthesized. Solution and solid-state structure of free macrocycles indicates an inversion of two pyrrole rings resulting in...

Using „spectrally dispersed’ impulsive stimulated Raman spectroscopy, vibrational spectra arising from motion of nuclear wavepackets in ground and excited electronic states of iodine in carbon tetrachloride are recorded isolating from solvent modes.

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