A study of electron transfer in Ru(dcbpy)2(NCS)2 sensitized nanocrystalline TiO2 and SnO2 films induced by red-wing excitation

Excited state dynamics and electron transfer from the Ru(dcbpy)2(NCS)2 (RuN3) sensitizer to semiconductor nanoparticles were studied using time-resolved femtosecond absorption spectroscopy. We found that excitation of the red wing of the absorption spectrum of the sensitizer populates the (3)MLCT state directly, both in solution and attached on semiconductor nanoparticle films. Electron injection is slowed down and becomes gradually less efficient as excitation moves towards red from the absorption maximum at 535 nm. At 675 nm the injection is non-exponential and characterized by 5, 30 and 180 ps time constants. The non-exponential electron injection observed is assigned to injection from a distribution of triplet states with energies below the semiconductor conduction band edge.     

Theoretical study of low-lying triplet states of aniline

Multireference complete active space self-consistent-field CASSCF(10,12)/ANO and second-order perturbation theory MS-CASPT2 calculations were performed to determine the vertical low-lying singlet and triplet states of aniline. The sequence of the seven lower lying triplet states is T1(1(3)A'), T2(1(3)A' '), T3(2(3)A'), T4(3(3)A'), T5(2(3)A' '), T6(4(3)A'), and T7(3(3)A' '). The 3(3)A', 4(3)A', and 3(3)A' ' states are assigned as 3s, 3py, and 3pz Rydberg states, respectively, while other states correspond to pi <-- pi excitations. Both the T1 and T2 states are found to be below at the lowest-lying singlet S1 (1(1)A' ') state. Geometry, vibrational modes, and electron distribution of the lowest lying T1 state were determined using UB3LYP calculations. The vertical and adiabatic singlet-triplet energy gaps DeltaE(S0-T1) amount to 3.7 and 3.5 +/- 0.2 eV, respectively. In clear contrast with the S0 state, the triplet aniline is no longer aromatic, and its protonation occurs preferentially at the ring meta-carbon site, with a proton affinity PA = 243 +/- 3 kcal/mol.     

Opto-electronic properties of CuAlO2

CuAlCO₂ is a p-type semiconductor with an average hole mobility of $\text{1.1 × 10}{}^{\mathrm{?7}}\text{m}{}^2\text{Vs}$. From photoelectrochemical measurements its bandgap is found to be indirect allowed at 1.65 eV; other interband transitions are at 2.3 and 3.5 eV. The valence band is made up mainly from Cu-3d wave functions and lies 5.2 eV below the vacuum level.     

A novel thermal rearrangement of N-cyano-N-(α-cyanobenzhydryl)-aniline

The title compound1 is rearranged, when refluxed with toluene, to the carbodiimide5 and the cyanoaniline7. While rearrangements analogous to the transformation1→5 have recently been observed, the transformation1→7 is novel.     

Charged-pion photoproduction measurement on deuterium in the Δ(1236) region using a quasi-monochromatic photon beam

Charged-pion photoproduction spectra on hydrogen and deuterium have been measured using an in-flight positron annihilation photon beam. Pions were detected in magnetic spectrometers. The experiment consisted of π^± angular distributions at 300 MeV, and fixed-angle excitation curves at 20° (π^±) and 55° (π^±) in the photon energy range 300–460 MeV. Experimental data are compared to a calculation by Laget which includes final-state nucleon-nucleon interaction and Pauli correlations. The overall agreement is satisfactory; however, the model slightly overestimates the nucleon-nucleon rescattering contribution.