Abstract In this work, the photochemistry of antidepressant paroxetine (PXT) and its photochemical fate in surface waters were investigated. The direct photolysis quantum yield, as well second-order rate constants reactions between PXT photochemically produced reactive intermediates (i.e., HO•, 3CDOM* 1O2) assessed with steady-state irradiation experiments, while reaction constant CO3•? was kno...

Photoinhibition is a state of physiological stress that occurs in all oxygen evolving photosynthetic organisms exposed to light. The primary damage occurs within the reaction center of Photosystem II (PS II). While irreversible photoinduced damage to PS II occurs at all light intensities, the efficiency of photosynthetic electron transfer decreases markedly only when the rate of damage exceeds ...

Abstract The current research was carried out to evaluate the stress tolerance potential of durum wheat plants, in response inoculation native plant growth-promoting bacteria (PGPB), through assessing PSII photochemistry and photosynthetic traits, as well grain yield height, investigate possibility using PGPB a sustainable alternative or combination with traditional fertilization plans. A green...

Excited-state chemistry is usually ascribed to photo-induced processes, such as fluorescence, phosphorescence, and photochemistry, or to bio- and chemiluminescence, in which light emission originates from a chemical reaction. A third class of excited-state chemistry is, however, possible. It corresponds to the photochemical phenomena produced by chemienergizing certain chemical groups without l...

In the preceding article [Pure Appl. Chem. 71, 303–320 (1999)] we examined two principal features of heterogeneous photocatalysis that demanded scrutiny: (i) description of photocatalysis and (ii) description of process efficiencies. For the latter we proposed a protocol relative photonic efficiency which could subsequently be converted to quantum yields. A difficulty in expressing a quantum yi...

Broadband UV-visible femtosecond transient absorption spectroscopy and steady-state integrated fluorescence were used to study the excited state dynamics of 7-dehydrocholesterol (provitamin D(3), DHC) in solution following excitation at 266 nm. The major results from these experiments are: (1) The excited state absorption spectrum is broad and structureless spanning the visible from 400 to 800 ...

Proteorhodopsin is an ion-translocating member of the microbial rhodopsin family. Light absorption by its retinal chromophore initiates a photocycle, driven by trans/cis isomerization, leading to transmembrane translocation of a proton toward the extracellular side of the cytoplasmic membrane. Here we report a study on the photoisomerization dynamics of the retinal chromophore of proteorhodopsi...

This exposition summarizes a personal perspective on past and current developments in organic photochemistry. It comprises three portions. The first section describes the beginnings of our photochemical studies and how it was possible to relate photochemical reactivity to excited-state electronic structures. The second selectively relates some of the reactions and concepts developed in the inte...