[en] A photogalvanic effect has been found on irradiation of an acetonitrile solution of hydrated uranyl nitrate. The maximum voltage obtained is 0.6V. The influence of concentration, wavelength, cell geometry upon the electrical yield are shown. The suggested mechanism relies on the oxydation of water by the excited uranyl ion

[en] This Booklet contains the abstracts of the invited lectures, courses and contributions to the IV International Symposium and School on Photobiology, Photophysics and Photochemistry FOTOCIENCIAS 2008 (National Capitol, Havana, Cuba, December 1rst to 6, 2008). FOTOCIENCIAS has been an interesting Scientific Meeting along its editions for researchers of many countries, especially from Latin America. In each FOTOCIENCIAS the participants have learned and taught a lot. Therefore, FOTOCIENCIAS has become an important forum for scientific interchange in the fields of Photobiology, Photophysics and Photochemistry. We also wish to remark our acknowledgment to all the sponsors of FOTOCIENCIAS 2008. We hope you will enjoy FOTOCIENCIAS 2008 and Havana We thank all the authors for their contributions to FOTOCIENCIAS 2008. (author)

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[en] Highlights: Excitation of the ^15ZP_g state of RcaE photoreceptor generates three primary photoproducts. Only the Lumi-G_o, photoproduct propagates to generate the ^15EP_r state. Excitation of ^15EP_r generates the Lumi-R_f photoproduct with an anomalously long living lifetime. Cyanobacteriochrome RcaE regulates Type III complementary chromatic adaption in the cyanobacterium Fremyella diplosiphon by photoswitching between a green-absorbing dark state (^15ZP_g) and red-absorbing photoproduct (^15EP_r). Ultrafast photodynamics of RcaE involve tautomerization of the bilin chromophore, inhomogeneity, and the generation of three primary photointermediates in the forward reaction (Lumi-G_o, Lumi-G_r, and Lumi-G_f). The secondary photodynamics reported here show that only Lumi-G_o evolves to ^15EP_r via spectrally similar Meta-G_o1 and Meta-G_o2 intermediates, with a protonation reaction occurring at the final step on the millisecond timescale. Reverse reaction dynamics were characterized and reveal an unusually long-lived Lumi-R_f photoproduct and a blue-shifted Meta-R_y intermediate.

[en] Photochemistry has been influenced greatly by the application of lasers as excitation sources. Comparisons are made below to illustrate this impact and to show how lasers have revolutionized this research field

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[en] Two pheomelanin model compounds were prepared and their photochemistries examined. Upon irradiation, an oxygen-mediated photopolymerization reaction was observed. The photopolymers obtained were characterized by their apparent molecular weights, UV and fluorescence spectra. The implications of these findings with respect to the structure and photobiology of pheomelanin are discussed. (author)