Cluster expansion of the wavefunction. Pseudo‐orbital theory based on the SAC expansion and its application to the spin density of open‐shell systems

1978 ◽  
Vol 68 (9) ◽  
pp. 4279-4291 ◽  
Author(s):  
H. Nakatsuji ◽  
K. Hirao
Keyword(s):  
Spin Density ◽  
Cluster Expansion ◽  
Open Shell ◽  
Orbital Theory

scholarly journals LOCALLY PROJECTED MOLECULAR ORBITAL THEORY FOR MOLECULAR INTERACTION WITH A HIGH-SPIN OPEN-SHELL MOLECULE

2006 ◽  
Vol 05 (04) ◽  
pp. 819-833 ◽  
Author(s):  
SUEHIRO IWATA
Keyword(s):  
Molecular Orbital ◽  
High Spin ◽  
Closed Shell ◽  
Open Shell ◽  
Coefficient Matrix ◽  
Molecular Orbitals ◽  
Orbital Method ◽  
Stationary Condition ◽  
Orbital Theory ◽  
Stationary Conditions

Locally projected molecular orbital method for molecular interactions is extended to a cluster consisting of a high-spin open-shell molecule and many closed-shell molecules. While deriving the equations, the Hartee–Fock–Roothaan equation without the orthonormal condition is obtained. The stationary conditions for molecular orbitals are expressed in a form of a generalized Brillouin condition. To obtain the molecular orbital coefficient matrix, which satisfies the stationary condition, a single Fock operator form is presented. For the locally projected molecular orbitals for the open-shell cluster, the working matrix representaion is given.

A Cluster Expansion Formalism for Direct Calculation of Ionisation Potential and Excitation Energy of Many Electron Systems Using H-F Ground State as Vacuum

1978 ◽  
Vol 33 (12) ◽  
pp. 1549-1551
Author(s):  
D. Mukherjee ◽  
A. Mukhopadhyay ◽  
R. K. Moitra
Keyword(s):  
Excitation Energy ◽  
Cluster Expansion ◽  
Ground State ◽  
Shell Theory ◽  
State Energy ◽  
Direct Calculation ◽  
Electron System ◽  
Open Shell ◽  
Electron Systems ◽  
Ionisation Potential

Abstract In this note, the authors’ recently developed non-perturbative open-shell theory is adapted for direct calculation o f ionisation potential and excitation energy of m any-electron systems. The H -F ground state is used as the “vacuum ” or “ core” in order to achieve a transparent separation o f the ground state energy. An application to a simple 4 π-electron system is discussed as an illustration o f the workability of the theory.

A MATHEMATICAL FORMULATION FOR FREE SPIN DENSITY AND ELECTRONIC DENSITY OF STATES IN K2CuCl4 · 2H2O-TYPE CRYSTALS

2002 ◽  
Vol 16 (20) ◽  
pp. 751-756 ◽  
Author(s):  
M. A. GRADO-CAFFARO ◽  
M. GRADO-CAFFARO
Keyword(s):  
Theoretical Model ◽  
Spin Density ◽  
Molecular Orbital ◽  
Density Of States ◽  
Mathematical Formulation ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Electronic Density ◽  
Electronic Density Of States ◽  
Molecular Bonding

A theoretical model based upon molecular orbital theory for superexchange interaction in K 2 CuCl 4 · 2H 2 O -type crystals is presented; atomic d- and p-orbitals as well as molecular bonding and antibonding orbitals are considered. In particular, the free spin density and the electronic density of states are calculated.

scholarly journals Linear Response Functions of Densities and Spin Densities for Systematic Modeling of the QM/MM Approach for Mono- and Poly-Nuclear Transition Metal Systems

Molecules ◽  
2019 ◽  
Vol 24 (4) ◽  
pp. 821
Author(s):  
Colin Kitakawa ◽  
Tomohiro Maruyama ◽  
Jinta Oonari ◽  
Yuki Mitsuta ◽  
Takashi Kawakami ◽  
...  
Keyword(s):  
Quantum Mechanics ◽  
Transition Metal ◽  
Spin Density ◽  
Linear Response ◽  
Transition Metal Ions ◽  
Open Shell ◽  
Reaction Centers ◽  
Oxygen Evolving ◽  
The Relationship ◽  
Spin Densities

We applied our analysis, based on a linear response function of density and spin density, to two typical transition metal complex systems-the reaction centers of P450, and oxygen evolving center in Photosystem II, both of which contain open-shell transition metal ions. We discuss the relationship between LRF of electron density and spin density and the types of units and interactions of the systems. The computational results are discussed in relation to quantum mechanics (QM) cluster and quantum mechanics/molecular mechanics (QM/MM) modeling that are employed to compute the reaction centers of enzymes.

Oxophenalenoxyl: Novel stable neutral radicals with a unique spin-delocalized nature depending on topological symmetries and redox states

2008 ◽  
Vol 80 (3) ◽  
pp. 507-517 ◽  
Author(s):  
Yasushi Morita ◽  
Shinsuke Nishida ◽  
Junya Kawai ◽  
Takeji Takui ◽  
Kazuhiro Nakasuji
Keyword(s):  
Spin Density ◽  
Open Shell ◽  
Two Stage ◽  
Neutral Radical ◽  
Redox States ◽  
Density Distributions ◽  
Alternant Hydrocarbon ◽  
Redox Ability ◽  
Unique Spin ◽  
Oxygen Atoms

Stable organic open-shell systems have attracted much attention in the field of molecule-based magnetism. We have been exploring novel stable neutral radicals based on a phenalenyl system known as an odd-alternant hydrocarbon π-radical with a highly spin-delocalized nature. Recently, we have designed and synthesized novel oxophenalenoxyl neutral radical systems possessing two oxygen atoms on the phenalenyl skeleton. These systems are unique in comprising some topological isomers depending on the positions of oxygen substituents on the phenalenyl skeleton. The isomers exhibit different topological symmetries of spin density distributions (spin topological symmetry control). In addition, two-stage one-electron reductions of these systems give the corresponding radical dianions, which show remarkably different topological symmetries of a spin-delocalized nature from those of the neutral radical systems (redox-based spin diversity). In this paper, we discuss the unique spin-delocalized nature of 3-, 4-, and 6-oxophenalenoxyl systems in view of the topological symmetry and redox ability, emphasizing the results from the radical dianion of 4-oxophenalenoxyl system from both experimental and theoretical sides.

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