The best technically feasible values for the triplet-singlet energy gap and the enthalpies of formation of the HCCl and CCl2 radicals have been determined through the focal-point approach. The electronic structure computations were based on high-level coupled cluster (CC) methods, up to quadruple excitations (CCSDTQ), and large-size correlation-consistent basis sets, ranging from aug-cc-pVDZ to...

The knowledge of photochemical kinetics in colloidal systems is important in understanding environmental photochemistry on dispersed solid surfaces. As model materials for the chemically sorbed organic compounds present in natural environments, modified silica nanoparticles (NPs) were obtained here by condensation of the silanol groups of fumed silica nanoparticles with 4-methoxybenzyl alcohol....

Singlet fission, the splitting of one singlet into two triplets, can potentially increase the efficiency of optoelectronic devices beyond conventional limits. Among the singlet fission molecules discovered to date, two mechanisms have emerged: intraor intermolecular singlet fission. Here we show a combined intrato intermolecular singlet fission mechanism in the model system of diphenyl-dicyano-...

A theoretical study of the low-lying singlet and triplet electronic states of BrONO2 is presented. Calculations of excitation energies and oscillator strengths are reported using excited-state coupled cluster response methods, as well as the complete active space self-consistent field method with the full Breit–Pauli spin-orbit operator. The calculations predict that there is only one singlet s...

Different porphyrin conformations are believed to play a role in controlling the cofactor properties in natural tetrapyrrole-protein complexes. In order to study the correlation between macrocycle nonplanarity and physicochemical properties in detail, a series of six porphyrins with graded degree of macrocycle distortion was investigated. These conformationally designed porphyrins are based on ...

For the reaction of O((3)P) with propyne, the product channels and mechanisms are investigated both theoretically and experimentally. Theoretically, the CCSD(T)//B3LYP/6-311G(d,p) level of calculations are performed for both the triplet and singlet potential energy surfaces and the minimum energy crossing point between the two surfaces are located with the Newton-Lagrange method. The theoretica...

Photon absorption by carbon nanotubes creates bound electron-hole pairs called excitons, which can exist in spin-polarized triplet or spin-unpolarized singlet configurations. Triplet excitons are optically inactive owing to the weak spin-orbit coupling in nanotubes. This prevents the optical injection of electron spin into nanotubes for spintronic applications and limits the efficiency of photo...

The (p ,d*) pickup reaction, leading to spin-singlet and spin-triplet continuum final states of the np system, is treated within the adiabatic approximation. Calculations are carried out for the C(p ,d*) and C(p ,d) reactions at 35 MeV, leading to the ground and 4.44 MeV states of C, for which new data have recently been reported. The np relative energy dependence of the (p ,d*) cross sections ...

Copper nitrenes are of interest as intermediates in the catalytic aziridination of olefins and the amination of C-H bonds. However, despite advances in the isolation and study of late-transition-metal multiply bonded complexes, a bona fide structurally characterized example of a terminal copper nitrene has, to our knowledge, not been reported. In anticipation of such a report, terminal copper n...