Excitation energies with linear response density matrix functional theory along the dissociation coordinate of an electron-pair bond in N-electron systems

2014 ◽  
Vol 140 (2) ◽  
pp. 024101 ◽  
Author(s):  
R. van Meer ◽  
O. V. Gritsenko ◽  
E. J. Baerends
Keyword(s):  
Density Matrix ◽  
Linear Response ◽  
Electron Pair ◽  
Pair Bond ◽  
Electron Systems ◽  
Excitation Energies ◽  
Functional Theory

scholarly journals Excitation energies with time-dependent density matrix functional theory: Singlet two-electron systems

2009 ◽  
Vol 130 (11) ◽  
pp. 114104 ◽  
Author(s):  
K. J. H. Giesbertz ◽  
K. Pernal ◽  
O. V. Gritsenko ◽  
E. J. Baerends
Keyword(s):  
Density Matrix ◽  
Time Dependent ◽  
Electron Systems ◽  
Excitation Energies ◽  
Functional Theory ◽  
Dependent Density

Density matrix functional theory of four-electron systems

2003 ◽  
Vol 119 (22) ◽  
pp. 11570-11573 ◽  
Author(s):  
Jerzy Cioslowski ◽  
Marcin Buchowiecki ◽  
Paul Ziesche
Keyword(s):  
Density Matrix ◽  
Electron Systems ◽  
Functional Theory

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.

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