Theoretical studies of theg-shift for Cr4+ions in GaN crystal from crystal-field and charge-transfer mechanisms

2001 ◽  
Vol 13 (33) ◽  
pp. 7459-7464 ◽  
Author(s):  
Zheng Wen-Chen ◽  
Wu Shao-Yi ◽  
Zi-Jian
Keyword(s):  
Charge Transfer ◽  
Crystal Field ◽  
Theoretical Studies ◽  
Gan Crystal ◽  
Transfer Mechanisms

scholarly journals Studies Of The G Factor For Cr4+ Ion In Bi4ge3o12 Crystal From Crystal-Field And Charge-Transfer Mechanisms

2004 ◽  
Vol 59 (7-8) ◽  
pp. 467-470
Author(s):  
Xiao-Xuan Wu ◽  
Wen-Chen Zheng ◽  
Sheng Tang
Keyword(s):  
Field Theory ◽  
Charge Transfer ◽  
Crystal Field ◽  
Order Perturbation ◽  
Cluster Approach ◽  
Crystal Field Theory ◽  
Third Order ◽  
Reasonable Explanation ◽  
Transfer Mechanisms ◽  
G Factors

The complete third-order perturbation formulas of the g factors g|| and g⊥ for 3d2 ions in tetragonal MX4 clusters have been obtained by a cluster approach. In these formulas, in addition to contributions to the g factors from the crystal-field mechanism in the crystal-field theory, the contributions from the charge-transfer mechanism are included. From these formulas, the g factors g|| and g⊥ for a Cr4+ ion in a Bi4Ge3O12 crystal are calculated. The results agree with the observed values. The calculated Δ gi(i = || or ⊥) value due to the charge-transfer is opposite in sign and about 20% greater than that due to the crystal-field mechanism. So, for the 3dn ions having a high valence in crystals, a reasonable explanation of the g factors should take both the crystal-field and charge-transfer mechanisms into account.

Studies of the EPR g-Shift of [Cr(CN)6]3– Clusters due to Crystal-Field and Charge-Transfer Mechanisms

2007 ◽  
Vol 62 (3-4) ◽  
pp. 218-220 ◽  
Author(s):  
Xiao-Xuan Wu ◽  
Wen-Ling Feng ◽  
Wang Fang ◽  
Wen-Chen Zheng
Keyword(s):  
Field Theory ◽  
Charge Transfer ◽  
Crystal Field ◽  
Transition Metal Ions ◽  
Theoretical Explanation ◽  
Crystal Field Theory ◽  
Absolute Value ◽  
Metal Cyanide ◽  
Cluster A ◽  
Transfer Mechanisms

The EPR g-shift Δg (≈ g−ge) of the metal-cyanide cluster [Cr(CN)6]3− is calculated by high-order perturbation formulas based on both the crystal-field (CF) and charge-transfer (CT) mechanisms (the latter is often neglected in the crystal-field theory). The result agrees with the experimental value. The sign of the g-shift ΔgCT due to the contribution of the CT mechanism is opposite to that of ΔgCF due to the contribution of the CF mechanism, and the absolute value of ΔgCT is about 34% of that of ΔgCF. It appears that for transition metal ions in a strong covalent cluster, a reasonable theoretical explanation of the g-shift should take both the CF and CT mechanism into account.

THEORETICAL STUDIES ON THE GYROMAGNETIC FACTORS FORFe3+INZnX(X=O,S,Se,Te)

2010 ◽  
Vol 24 (17) ◽  
pp. 1891-1898 ◽  
Author(s):  
XUE-FENG WANG ◽  
SHAO-YI WU ◽  
PEI XU ◽  
LI-LI LI
Keyword(s):  
Experimental Data ◽  
Charge Transfer ◽  
Crystal Field ◽  
Reasonable Agreement ◽  
Model Parameters ◽  
Theoretical Studies ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Cluster Approach ◽  
Perturbation Formula

The gyromagnetic factors for Fe3+in ZnX ( X = O , S , Se , Te ) are theoretically studied from the perturbation formula of the g-factor for a 3d5ion in tetrahedra based on inclusion of both the crystal-field and the charge-transfer contributions. The related model parameters in the calculations are determined from the cluster approach in a uniform way. The g-shift Δg (= g-gs, where gs≈ 2.0023 is the spin-only value) from the charge-transfer contributions is opposite (positive) in sign and much larger in magnitude as compared with that from the crystal-field ones. The importance of the charge-transfer contributions increases rapidly with increasing the covalency and the spin-orbit coupling coefficient of the ligand and thus exhibits the order of O2-< S2-< Se2-< Te2-. The calculated g-factors by considering both the crystal-field and charge-transfer contributions show reasonable agreement with the experimental data for all the Fe3+centers in ZnX .

THEORETICAL STUDIES ON THE COUPLING INTERACTIONS AND SELF-EXCHANGE REACTION MECHANISMS IN THE COMPLEXES OF NO WITH ONH AND NOH

2008 ◽  
Vol 07 (03) ◽  
pp. 435-446 ◽  
Author(s):  
PING LI ◽  
XIAOYAN XIE ◽  
YUXIANG BU ◽  
WEIHUA WANG ◽  
NANA WANG ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Exchange Reaction ◽  
Reaction Mechanisms ◽  
Natural Bond Orbital ◽  
Theoretical Studies ◽  
Exchange Reactions ◽  
Electron Transfer Mechanism ◽  
Proton Coupled Electron Transfer ◽  
Planar Geometries ◽  
Transfer Mechanisms

The coupling interactions and self-exchange reaction mechanisms between NO and ONH (NOH) have been systematically investigated at the B3LYP/6-311++G** level of theory. All the equilibrium complexes are characterized by the intermolecular H-bonds and co-planar geometries. The cisoid NOH/ON species is the most stable one among all the complexes considered due to the formation of an N – N bond. Moreover, all the cisoid complexes are found to be more stable than the corresponding transoid ones. The origin of the blueshifts occurring in the selected complexes has been explored, employing the natural bond orbital (NBO) calculations. Additionally, the proton transfer mechanisms for the self-exchange reactions have been proposed, i.e. they can proceed via the three-center proton-coupled electron transfer or five-center cyclic proton-coupled electron transfer mechanism.

Theoretical Studies of the Excited States and Intra-ionic Charge Transfer of O-3

1996 ◽  
Vol 12 (02) ◽  
pp. 97-101
Author(s):  
Cao Ze-Xing ◽  
◽  
Huang Hong-Xin ◽  
Tian An-Min
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Theoretical Studies ◽  
Ionic Charge

scholarly journals Ab-Initio Study of the Electronic and Magnetic Properties of Boron- and Nitrogen-Doped Penta-Graphene

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 816 ◽  
Author(s):  
Chao Zhang ◽  
Yu Cao ◽  
Xing Dai ◽  
Xian-Yong Ding ◽  
Leilei Chen ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Charge Transfer ◽  
First Principles ◽  
Magnetic Moments ◽  
First Principles Calculations ◽  
Electronic Band ◽  
Magnetic Devices ◽  
Spin Polarized ◽  
Electronic Band Gap ◽  
Transfer Mechanisms

First-principles calculations were performed to investigate the effects of boron/nitrogen dopant on the geometry, electronic structure and magnetic properties of the penta-graphene system. It was found that the electronic band gap of penta-graphene could be tuned and varied between 1.88 and 2.12 eV depending on the type and location of the substitution. Moreover, the introduction of dopant could cause spin polarization and lead to the emergence of local magnetic moments. The main origin of the magnetic moment was analyzed and discussed by the examination of the spin-polarized charge density. Furthermore, the direction of charge transfer between the dopant and host atoms could be attributed to the competition between the charge polarization and the atomic electronegativity. Two charge-transfer mechanisms worked together to determine which atoms obtained electrons. These results provide the possibility of modifying penta-graphene by doping, making it suitable for future applications in the field of optoelectronic and magnetic devices.

Sign in / Sign up

Export Citation Format

Share Document