Photoinduced primary charge-separation and charge-recombination are characterized by a combination of time-resolved optical and EPR measurements of a fullerene-porphyrin-linked triad that undergoes fast, stepwise charge-separation processes. The electronic coupling for the energy-wasting charge recombination is evaluated from the singlet-triplet electronic energy gap in the short-lived, primary...

Electronic structure calculations at the CASSCF and UB3LYP levels of theory with the aug-cc-pVDZ basis set were used to characterize structures, vibrational frequencies, and energies for stationary points on the ground state triplet and singlet O(2)+C(2)H(4) potential energy surfaces (PESs). Spin-orbit couplings between the PESs were calculated using state averaged CASSCF wave functions. More a...

Photoinduced intra-molecular energy transfer in two ketoprofen(KP)-naproxol(NPX) diastereomers proceeds via two pathways. Very fast singlet–triplet energy transfer (k = 1.2 · 10 s ) from KP to NPX occurs for a small percentage (6%) and the major pathway is triplet–triplet energy transfer (k 3 · 10 s ). This was shown with femtosecond transient absorption spectroscopy and global and target analy...

The title compound, C18H17NO5, was prepared by a synthetic strategy based on the Heck reaction from Morita-Baylis-Hillman adducts. The five-membered ring adopts a slightly twisted conformation on the Ca-Cm (a = aromatic and m = methyl-ene) bond. The dihedral angle between the five-membered ring and the spiro aromatic ring is 89.35 (7)°; that between the five-membered ring and the 4-meth-oxy-ben...

Codeposition of thermally generated atomic germanium vapor and nitrous oxide (N(2)O) in Ar onto a substrate at 11 K produced infrared absorption lines in several sets. The most prominent comprises intense lines at 1443.7, 1102.4, and 784.0 cm(-1) that become diminished upon irradiation with UV or visible light. These lines are attributed to nu(1) (NO stretching), nu(2) (NN+GeN stretching), and ...

The reactions dynamics of the dicarbon molecule C2 in the 1Sigma (g)+ singlet ground state and 3Pi(u) first excited triplet state with allene, H2CCCH2(X1A1), was investigated under single collision conditions using the crossed molecular beam approach at four collision energies between 13.6 and 49.4 kJ mol(-1). The experiments were combined with ab initio electronic structure calculations of the...

Structure and bonding for a series of oxo-bridged and sulphur bridged alkali-metal centers (M-X-M: Li, Na and K; X = O, S) are studied for various M-X-M angles. The structures for these charge-transfer systems are compared with H-X-H. These chargetransfer systems show bonding and structures that are distinctively different from the covalent H-X-H molecules. The singlet-triplet gap for all of th...

Under strong light conditions, long-lived chlorophyll triplets ((3)Chls) are formed, which can sensitize singlet oxygen, a species harmful to the photosynthetic apparatus of plants. Plants have developed multiple photoprotective mechanisms to quench (3)Chl and scavenge singlet oxygen in order to sustain the photosynthetic activities. The lumenal loop of light-harvesting chlorophyll a/b complex ...

The adiabatic description of molecular electronic states is based on potential energy surfaces, defined by the motion of the electrons, on which the slower nuclear motions (vibrations and rotations) occur. However, this model breaks down when relativistic effects such as the coupling between the electron spin and its orbital angular momentum (spin-orbit coupling) are taken into account. The res...