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Photophysics of Lumichrome and Its Analogs

Sikorska E., Worrall D., Bourdelande J., Sikorski M.

Polish Journal of Chemistry

2003

Vol. 77 / nr 1

65-73

The spectroscopic and photophysical properties of lumichrome and its 1- and 3-methyl and 1,3-dimethyl derivatives in acetonitrile and in methanol are presented. In common with the parent molecule, the photophysics of the lumichrome methyl derivatives are dominated by non-radiative transitions in both methanol and acetonitrile. However, fluorescence yields in methanol are higher than in acetonitrile as a result of a reduction in the efficiency of non-radiative deactivation channels. These observations are discussed in terms of the available solvent-solute interactions.

Theoretical studies on sulfur-containing radical ions

Carmichael I.

Nukleonika

2000

Vol. 45, nr 1

11-17

Structures and properties are reported for pi-radical cations and for sigma-radical cations and anions, containing SS, SN and SO odd-electron bonds, from a variety of ab initio molecular orbital techniques and Density Functional Theory (DFT). Characteristic frequencies and absorption bands are determined to aid in the assignment of transient vibrational and optical spectra detected in pulse radiolysis experiments. Hyperfine coupling tensors are evaluated to facilitate the identification of these radicals by EPR spectroscopy. By comparison with predictions from accurate coupled-cluster based calculations in some simple model systems, DFT is shown to have difficulties in correctly describing the electronic structure of these radical ions. Useful linear relationships are uncovered between the computed lenght of the odd-electron bond and both the wavelenght of maximum optical absorption and the bond stretching frequency.

Transient absorption experimental set-up with femtosecond time resolution

Naskręcki R., Lorenc M., Ziółek M., Karolczak J., Kubicki J., Maciejewski A., Szymański M.

Bulletin of the Polish Academy of Sciences. Chemistry

1999

Vol. 47, No. 4

333-346

Experimental set-up for time dependent transient absorption/gain measure-ments with femtosecond time resolution is presented. The pump-probe spectroscopy tech-nique with femtosecond pulses from Ti: Sapphire laser system (Spectra Physics) allowed measurements of the optical density of transient absorption and transient gain in the spectral range of 330-700 nm, time resolution of 120 fs, and the accuracy of up to 0.005. The real time resolution and "zero time" dispersion of the system were found in two-photon absorption experiment.