The involvement of upper electron-excited states in bacterial bioluminescence process was studied with excitation energy-accepting molecules. The fluorescent aromatic compounds, anthracene and 1.4-bis(5-phenyloxazol-2-yl)benzene, were chosen. Energies of their lowest excited singlet states are higher than the energy of the analogous state of the bioluminescence emitter; their absorption spectra and bioluminescence do not overlap. Hence, the excitation of these molecules by singlet-singlet energy transfer or by light absorption is excluded. Sensitized fluorescence of these compounds in the bioluminescence systems has been recorded, indicating the activity of upper electron-excited states in the bioluminescent process.

535:530.182 Fluorescence of symmetric polymethine dye solutions ( max abs λ ≈ 700 nm) upon anti-Stokes excitation by cw radiation of a titanium-sapphire laser (781 nm) is first investigated. A series of six compounds with analogous composition and spectral and luminescent properties is investigated. It is demonstrated that in addition to the anti-Stokes component, the Stokes component with a maximum at 820 nm (referred to the Н-aggregates of initial dyes) is observed in the fluorescence spectra of solutions of the examined molecules when dye concentration increases to 10 -3 M. Dependences of the anti-Stokes and Stokes component intensities on the exciting radiation power are obtained that confirm a linear excitation character. On examples of xanthene and polymethine dyes, the use of organic fluorophors for anti-Stokes laser cooling and some other possible applications of the anti-Stokes fluorescence are discussed.

The energy localisation in the case of spherical symmetry advanced previously is justified in reference to an exact interior solution which is a generalisation of the p = constant Schwarzschild solution. This reveals the inadequacy of the Tolman expression for localisation which also fails to provide the correct total mass for a system which exhibits certain discontinuities. A generalised localisation expression for arbitrary static systems is proposed for further consideration.

No abstract

No abstract