scholarly journals Analysis of two-orbital correlations in wave functions restricted to electron-pair states

2016 ◽  
Vol 94 (15) ◽  
Author(s):  
Katharina Boguslawski ◽  
Paweł Tecmer ◽  
Örs Legeza
Keyword(s):  
Electron Pair ◽  
Wave Functions

On the H− migration in the ion

1984 ◽  
Vol 62 (12) ◽  
pp. 1323-1327 ◽  
Author(s):  
J. Kalcher ◽  
P. Rosmus ◽  
M. Quack
Keyword(s):  
Potential Energy ◽  
Potential Energy Surface ◽  
Symmetry Group ◽  
Electron Pair ◽  
Energy Surface ◽  
Wave Functions ◽  
Molecular Symmetry ◽  
Electronic Wave ◽  
Self Consistent ◽  
Electronic Wave Functions

For the [Formula: see text] ion, the geometries and energies of several minima, and barriers between these, have been calculated from correlated self-consistent electron pair (SCEP) and coupled electron pair (CEPA) electronic wave functions. The spectroscopic and kinetic implications of the potential energy surface are discussed in terms of its molecular symmetry group.

Some wave functions for the four-electron threecentre bonding of four- and eight-π-electron systems

1974 ◽  
Vol 27 (4) ◽  
pp. 691 ◽  
Author(s):  
RD Harcourt ◽  
JF Sillitoe
Keyword(s):  
Molecular Orbital ◽  
Configuration Interaction ◽  
Electron Pair ◽  
Valence Bond ◽  
Pair Bond ◽  
Wave Functions ◽  
Electron Systems ◽  
Numerical Evidence ◽  
The One ◽  
Increased Valence

For symmetrical four-electron three-centre bonding units, the standard valence-bond (VB), delocalized molecular orbital (MO), increased-valence (IV) and non-paired spatial orbital (NPSO) representations of the electrons are Diagram O3, NO2- and CF2 with four π-electrons, and N3-, CO2 and NO2+ with eight π-electrons, have respectively one and two four-electron three-centre bonding units for these n-electrons. By means of Pople-Parr-Pariser type approximations, the MO, standard VB, IV and NPSO wave functions for these systems are compared with complete VB (or best configuration interaction) wave functions for the ground states. Similar studies are reported for the n-electrons of N2O. Further demonstration is given for the important result obtained elsewhere that the IV formulae must always have energies which are lower than those of the standard VB formulae, provided that the same technique is used to construct electron-pair bond wave functions. The extra stability arises because IV formulae summarize resonance between the standard VB formulae and long-bond formulae of the type Diagram As has been discussed elsewhere, the latter structure can make appreciable contributions to the complete VB resonance when its atomic formal charges are either zero or small in magnitude.If two-centre bond orbitals are used to construct the wave functions for the one-electron bond(s) and the two-electron bond(s) of IV formulae, then the IV and MO wave functions are almost identical for the symmetrical systems. Further numerical evidence is provided for this near-equivalence.

scholarly journals The electron-pair density distribution of the 1,3Πu excited states of H2

2016 ◽  
Vol 94 (12) ◽  
pp. 998-1001 ◽  
Author(s):  
J.M. Mercero ◽  
M. Rodríguez-Mayorga ◽  
E. Matito ◽  
X. Lopez ◽  
J.M. Ugalde
Keyword(s):  
Density Distribution ◽  
Excited States ◽  
Electron Pair ◽  
Distribution Functions ◽  
Wave Functions ◽  
Explicit Calculation ◽  
Pair Density ◽  
High Level ◽  
Electron Pair Density ◽  
Shielding Effects

The non-monotonic behavior of the electron repulsion energy and the inter-electronic distance, as a function of the internuclear separation, in the 3Πu excited state of the hydrogen molecule has been assessed by explicit calculation and analysis of the electron-pair density distribution functions from high level ab initio full configuration interaction wave functions, for both the 3Πu and the 1Πu states. Additionally, Hund’s rule as applied to these two states has been accounted for in terms of simple electronic shielding effects induced by wave function antisymmetrization.

Valence Bond Structures for the N3- Anion, the N3 Radical and the N6- Radical Anion

2012 ◽  
Vol 67 (9) ◽  
pp. 935-943 ◽  
Author(s):  
Richard D. Harcourta ◽  
Thomas M. Klapötke
Keyword(s):  
Radical Anion ◽  
Electron Pair ◽  
Atomic Orbital ◽  
Valence Bond ◽  
Wave Functions ◽  
The One ◽  
Lewis Structures ◽  
Increased Valence ◽  
Polarity Parameters

With Heitler-London atomic orbital-type formulations of the wave functions for (fractional) electron-pair πx(NN) and πy(NN) bonds, increased-valence structures for the N3- anion and N3- radical are equivalent to resonance between familiar standard Lewis structures and singlet diradical (or “long-bond”) Lewis structures. Theory is developed for the calculation of the polarity parameters that are associated with the one-electron πx(NN) and πy(NN) bonds in the increased-valence structures, and illustrative STO-6G estimates of their values are reported. They show that the πx and πy electrons of these bonds are strongly charge-correlated relative to each other. The increased-valence structures for the N3- anion and the N3- radical are used to help construct increased-valence structures for the N6- radical anion with C2h symmetry

Possible ferromagnetism of a free-electron pair

1979 ◽  
Vol 57 (2) ◽  
pp. 243-252
Author(s):  
S. Olszewski
Keyword(s):  
Triplet State ◽  
Magnetic Moment ◽  
Free Electron ◽  
Electron Pair ◽  
Singlet State ◽  
A Priori ◽  
Wave Functions ◽  
Mutual Position ◽  
Spin Magnetic Moment ◽  
Free Electron Pair

It is pointed out that the relation E(ΦA) < E(ΦS) holds for a free-electron pair within a potential box on condition that the assumptions of (i) the continuity of wave functions and their derivatives, (ii) very thin potential box, and (iii) weak Coulomb interaction between the electrons, are satisfied; E(ΦA) denotes the lowest energy of the triplet state of the pair with which a net spin magnetic moment may be associated E(ΦS) is the lowest energy of the nonmagnetic singlet state of the pair. Mutual position of E(ΦA) and E(ΦS) cannot be predicted a priori, as wave functions ΦA and ΦS fulfill different boundary conditions.

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