We study the symmetries of twisted trilayer graphene's band structure under various extrinsic perturbations, and analyze role long-range electron-electron interactions near first magic angle. The electronic is modified by these in a similar way to bilayer graphene. electron pairing due long-wavelength charge fluctuations, which are coupled among themselves via Coulomb interaction additionally m...

The combined effect of hydrostatic pressure and temperature on correlation energy in a triplet state of two electron spherical quantum dot with square well potential is computed. The result is presented taking GaAs dot as an example. Our result shows the correlation energies are i)negative in the triplet state contrast to the singlet state ii) it increases with increase in pressure  iii)further...

A theoretical investigation of the low-lying singlet and triplet electronic states of HOOOCl and HOOOBr is presented. Calculations of excitation energies and oscillator strengths using CASSCF, first-order CI, MRCI and the equation of motion coupled-cluster singles and doubles methods are presented. The calculations predict that for HOOOCl and HOOOBr there are two singlet states that are accessi...

In order to explain the reduced photodynamic (PDT) activity of a recently proposed m-tetra (hydroxyphenyl) porphycene derivative (temocene or THPPo) in terms of singlet oxygen quantum yields compared to porphyrin analogue Foscan (m-THPC), a time dependent DFT investigation has been carried out. Computed electronic transitions, singlet-triplet energy gaps and spin-orbit coupling matrix elements ...

s It is suggested that simple electronic shielding effects induced by wave function antisymmetrization tend to govern the energy ordering of singlet and triplet terms within a two-electron atomic configuration. This approach gives rise to the following alternating rule: For the term of greatest orbital angular momentum within a configuration, the triplet lies below the singlet. The energy order...

The full harvesting of both singlet and triplet excitons can pave the way toward more efficient molecular light-emission mechanisms (i.e., TADF or thermally activated delayed fluorescence) beyond t...

We construct the symmetry adapted low energy effective Hamiltonian for the electronic states in the vicinity of the Fermi level in iron based superconductors. We use Luttinger’s method of invariants, expanding about Γ and M points in the Brillouin zone corresponding to two iron unit cell, and then matching the coefficients of the expansion to the 5and 8-band models. We then use the method of in...

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...

Magnetic properties are studied of a system having two types of electronic singlet-ground-state ions, d-ion (singlet-doublet) and t-ion (singlet-triplet), by taking account of the hyperfine coupling. It is shown that the exchange interaction between the d-ion and the t-ion electronic spins affects crucially the magnetic properties. The results are discussed in connection with the experimental r...

Ab initio calculations have been performed on five singlet and five triplet isomers which are minima on the two lowest potential energy surfaces of Ti2H6. We have used single-configuration ROHF as well as multiconfigurational methods, employing triple-ζ with polarization basis sets. Dynamic correlation effects are accounted for using second-order perturbation methods. Staggered and eclipsed C3v...