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.

Electronic Structure Calculations of the Copper Oxygen Planes in Yba2Cu3O6+δ, for 0 < δ < 1

1989 ◽  
Vol 169 ◽  
Author(s):  
J. A. Cogordan
Keyword(s):  
Electronic Structure ◽  
Excited State ◽  
Ab Initio ◽  
Molecular Orbital ◽  
Lower Energy ◽  
Closed Shell ◽  
Electronic Structure Calculations ◽  
Open Shell ◽  
Molecular Orbitals ◽  
Structure Calculations

AbstractMolecular ab initio seIf-consistent calculations on clusters simulating the copper-oxygen layers in the Yba2Cu3O6;δ are reported. The electronic structure, of this layer, was computed for different sets of values of the lattice parameters (a,b,c), according to their dependence on the oxygen stiochiometry. For the molecular orbitals , two different electronic occupations are considered, a closed shell and an open shell. For the open shell, an electron has been excited to the first virtual molecular orbital. It is found that this excited state has lower energy than the closed shell configuration for 0 < δ < 1. Molecular energies an electronic population are reported.

Extension of the fragment molecular orbital method to treat large open-shell systems in solution

2015 ◽  
Vol 635 ◽  
pp. 86-92 ◽  
Author(s):  
Hiroya Nakata ◽  
Dmitri G. Fedorov ◽  
Kazuo Kitaura ◽  
Shinichiro Nakamura
Keyword(s):  
Molecular Orbital ◽  
Open Shell ◽  
Orbital Method ◽  
Molecular Orbital Method ◽  
Fragment Molecular Orbital

Molecular Orbitals and CH3, CH2, and CH Deformation Group Frequencies

1980 ◽  
Vol 34 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Norman B. Colthup
Keyword(s):  
Linear Relationship ◽  
Electron Density ◽  
Force Constant ◽  
Molecular Orbital ◽  
Interaction Force ◽  
Molecular Orbitals ◽  
Deformation Vibration ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Symmetrical Deformation

A linear relationship has been found between the wavenumber of the CH3 symmetrical deformation vibration and the electron density on the CH3 carbon as calculated from CNDO/2 molecular orbital theory. Other CH deformation vibrations are also related to the electron density on the carbon and, as a result, can be correlated with the CH3 symmetrical deformation wavenumber. These include ν̄(CH2 def), ν̄(CH2 wag) and both components of ν̄(CH wag). The splitting of ν̄(CH3 sym def) in isopropyl and t-butyl groups has long been known. It is shown here that the effect is due to an interaction force constant relating to the CH3 symmetrical deformation vibrations of two or three different neighboring CH3 groups. The origin of the interaction is thought to be an H,H′ repulsion between hydrogens on the different CH3 groups.

The Electronic Structures of A2Y4 Molecules

1963 ◽  
Vol 16 (5) ◽  
pp. 737 ◽  
Author(s):  
RD Brown ◽  
RD Harcourt
Keyword(s):  
Molecular Orbital ◽  
Electronic Structures ◽  
Lone Pair ◽  
Orbital Method ◽  
Molecular Orbital Theory ◽  
Bond Properties ◽  
Orbital Theory ◽  
The Core ◽  
Valence Electrons ◽  
Charge Rule

A study of the electronic structures of A2Y4 molecules containing 34, 36, and 38 valence electrons has been made. An approximate VESCF, molecular- orbital method was used, attention being concentrated mainly on the delocalization of σ-electrons which are classically regarded as lone-pairs on the Y atoms. The results provide explanations of the main features of many of the observed AA- and AY-bond lengths and YAY-bond angles of N2O4, C2O42-, B2F4, B2Cl4, C2F4, C2Cl4, S2O42-, and N2F4. Other A2Y4 systems which have either not been fully characterized or not yet reported are also considered. The extent of lone-pair delocalization is shown to be governed by a parameter aσ, related to the coulomb and resonance parameters of H�ckel molecular-orbital theory. General trends in the value of aσ can be predicted from values of the core charges of A and Y towards the o-electrons concerned. A more detailed "adjacent charge" rule emerges. It differs from the classical rule in that for A2Y4 systems, adjacent negative formal charges on the A atoms should not very greatly affect the AA-bond properties. Difficulties were encountered in consistently interpreting the properties of some A2F4 and A2Cl4 compounds. These deserve further attention.

scholarly journals The determination of molecular orbitals

1949 ◽  
Vol 198 (1052) ◽  
pp. 1-13 ◽  
Keyword(s):  
Molecular Orbital ◽  
Molecular Orbitals ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
Energy States ◽  
Molecular Framework

In the molecular orbital theory of valency the electrons are assigned to the whole molecule rather than to atoms or to other localized parts. While the method has advantages in dealing with the properties of a molecule as a whole, such as its energy states, the extension of each orbital over the molecular framework is a disadvantage when dealing with localized properties such as directed bonds. This paper deals in a general way with the equations which molecular orbitals must satisfy, allowing for the exchange of electrons between orbitals. It is then shown that when molecules have properties of symmetry the equations can be transformed so as to be satisfied by orbitals which have the property of equivalence. These can be regarded under certain conditions as directed orbitals and the conditions for these are discussed. To illustrate the method molecules of the type XY 2 are considered.

The molecular orbital theory of chemical valency. IV. The significance of equivalent orbitals

1950 ◽  
Vol 202 (1069) ◽  
pp. 166-180 ◽  
Keyword(s):  
Total Energy ◽  
Molecular Orbital ◽  
Molecular Orbitals ◽  
Molecular Orbital Theory ◽  
Orbital Theory ◽  
General Transformation ◽  
Lone Pairs ◽  
Simple Molecules

The theory of the transformation from molecular orbitals to sets of equivalent orbitals is discussed for the general case when there is more than one occupied molecular orbital of given symmetry and more than one equivalent set. The general transformation is worked out for molecules whose component atoms possess inner shells and lone pairs of electrons. The theory is illustrated by reference to some simple molecules such as water and ammonia. Finally, it is shown how the expression for the total energy of a molecule can be divided up in such a way that the interactions between its localized parts are dealt with separately. The significance of lone pairs of electrons in determining the shape of molecules is pointed out.

Sign in / Sign up

Export Citation Format

Share Document