Potential energy curves of the ground and a few excited states of the BrO and HOBr along the photodissociation reactions, which correlate with lower dissociation limits are obtained on the base of calculations results by ab initio method. The singlet-triplet nonadiabatic transition with dissociation of the ground ХΣ state to lower limit О(Р) + Br(S) is predicted on the basis of calculations res...

The O((3)P) + C(2)H(4) reaction, of importance in combustion and atmospheric chemistry, stands out as a paradigm reaction involving triplet- and singlet-state potential energy surfaces (PESs) interconnected by intersystem crossing (ISC). This reaction poses challenges for theory and experiments owing to the ruggedness and high dimensionality of these potentials, as well as the long lifetimes of...

A new method for extracting ensemble Kohn-Sham potentials from accurate excited state densities is applied to a variety of two-electron systems, exploring the behavior of exact ensemble density functional theory. The issue of separating the Hartree energy and the choice of degenerate eigenstates is explored. A new approximation, spin eigenstate Hartree-exchange, is derived. Exact conditions tha...

Excitement in the area of plasmonics stems from the ability to detect processes that are otherwise undetectable. Collective electron oscillations at metal surfaces experience strong spatial localization, which results in extremely intense and localized electromagnetic fields. This phenomenon is at the heart of all surface-enhanced spectroscopic processes. The intense local field can relax sever...

The spin-flip approach has been applied to calculate vertical and adiabatic energy separations between low-lying singlet and triplet states in diradicals. The spin-flip model describes both closedand open-shell singlet and ~low-spin! triplet states within a single reference formalism as spin-flipping, e.g., a→b , excitations from a high-spin triplet (M s51) reference state. Since both dynamical...

The singlet, open-shell singlet and triplet potential energy surfaces (PES) for the peroxo state of a catalytic functional tyrosinase model have been investigated by density functional theory calculations. The broken-symmetry solution exhibits considerable stabilisation over the whole PES but the importance of the triplet state is unravelled as well.

Multiwavelength time-resolved spectroscopy is employed to study the triplet-state photophysics of acridine yellow dissolved in a rigid saccharide glass. Activated reverse intersystem crossing from photoexcited triplet states to the fluorescent singlet state provides a temperaturedependent decay pathway of the triplet population. While a unimolecular relaxation of a homogeneous excited triplet p...

Chlorosomes comprise thousands of bacteriochlorophylls (BChl c, d, or e) in a closely packed structure surrounded by a lipid-protein envelope and additionally contain considerable amounts of carotenoids, quinones, and BChl a. It has been suggested that carotenoids in chlorosomes provide photoprotection by rapidly quenching triplet excited states of BChl via a triplet-triplet energy transfer mec...