using hartree-fock su-sheriffer-heeger (hf-ssh) model, we have studied the dependence of the energies of the ground (magnetic triplet state) and the first exited (nonmagnetic singlet state) states of the size-2 trigonal zigzag graphene nanoflake (size-2 nf) on the intensity of an external in plane static electric field at zero temperature. we identify a transition from the magnetic triplet stat...

The effects of halogens; fluorine, chlorine and bromine, on the stability and multiplicity of phenylcarbenes / silylenes/ germylenes structures are compared and contrasted at B3LYP/6-311++G**//B3LYP/6-31+G* level. The singlet-triplet energy gaps, ΔES-T , values for all the above speciesincrease through fluorinated up, ΔES-Ts and ΔEHOMO–LUMOs support the stability of the singlet statesinspite of...

Computations at the CASPT2, CBS-QB3, and B3LYP levels of theory demonstrate that -substitution of vinyl cations with π-donors switches the ground state of these ions from the familiar closedshell singlet state to a carbene-like triplet state similar to the electronic state of triplet phenyl cations. Although the parent vinyl cation is a ground-state singlet species with a very large energy gap ...

Computations at the CASPT2, CBS-QB3, and B3LYP levels of theory demonstrate that beta-substitution of vinyl cations with pi-donors switches the ground state of these ions from the familiar closed-shell singlet state to a carbene-like triplet state similar to the electronic state of triplet phenyl cations. Although the parent vinyl cation is a ground-state singlet species with a very large energ...

In this paper, we study the electronic properties of a concentric triple quantum ring using exact diagonalization technique. The energy spectra and magnetization for a single electron and two electrons, in the presence of an applied magnetic field, are calculated and discussed. It is shown that, for two-interacting electrons, the period of Aharonov-Bohm oscillations decreases to the half of tha...

Using Hartree-Fock Su-Sheriffer-Heeger (HF-SSH) model, we have studied the dependence of the energies of the ground (magnetic triplet state) and the first exited (nonmagnetic singlet state) states of the size-2 trigonal zigzag graphene nanoflake (size-2 NF) on the intensity of an external in plane static electric field at zero temperature. We identify a transition from the magnetic triplet stat...

the effects of halogens; fluorine, chlorine and bromine, on the stability and multiplicity of phenylcarbenes / silylenes/ germylenes structures are compared and contrasted at b3lyp/6-311++g**//b3lyp/6-31+g* level. the singlet-triplet energy gaps, δes-t , values for all the above speciesincrease through fluorinated up, δes-ts and δehomo–lumos support the stability of the singlet statesinspite of...

in this paper, we study the electronic properties of a concentric triple quantum ring using exact diagonalization technique. the energy spectra and magnetization for a single electron and two electrons, in the presence of an applied magnetic field, are calculated and discussed. it is shown that, for two-interacting electrons, the period of aharonov-bohm oscillations decreases to the half of tha...

Energy gaps, AXsar (X=E, H and G) (AX.,.,-=lia,„,,,InrX“dpka,) between single (s) and triplet (I) states werecalculated at B3LTP/6-3 I 1.HO" level of theory. Our results showed that electron donating substituents(G = -NHz, -OH. -CH), -F, -Cl and -Br) at phenyl group cause to increase and electron withdrawingsubstiluents (G -CF2. and -NO:) lead to decrease the singlet-triplet energy gaps of Ar -...

The iron oxide dimers (FeO)2 and their peroxide isomers are studied with the B3LYP density functional as bare clusters and as hexacarbonyls. Among the bare clusters the planar four-member ring structures are more stable than the non-planar ones and the rhombic dioxide Fe2O2 with antiferromagnetically ordered electrons on iron centers is the global minimum. Water adsorption on the bare diiron di...