Conformations and charge distributions in fluoronitrosoethylenes and nitrosoethylene

1990 ◽  
Vol 68 (5) ◽  
pp. 762-769 ◽  
Author(s):  
Cecilia Sarasola ◽  
Fernando P. Cossío ◽  
Jesus M. Ugalde
Keyword(s):  
Bond Energy ◽  
Electrostatic Potentials ◽  
Bond Orders ◽  
Nitroso Group ◽  
Electrophilic Attack ◽  
Potential Region ◽  
Contour Maps ◽  
Consistent Field ◽  
Self Consistent Field ◽  
Transoid Conformation

The optimized structures, bond orders, and electrostatic potentials for both transoid and cisoid fluoronitrosoethylenes and nitrosoethylene have been calculated by abinitio self-consistent-field molecular orbital procedure. The transoid structures are found to be of lower energy than the cisoids. Analyses of the calculated bond orders show that the C—C bond energy compares well with that of ethylene and the C—N bond energy with that of ethylamine, and therefore the contributions from ionic resonance structures are predicted to be small. The calculated electrostatic potential contour maps show that the presence of the nitroso group completely eliminates the negative potential region associated with the C—C double bond, thus rendering it less susceptible to electrophilic attack. Analyses of the values and relative locations of positive electrostatic potentials correctly predict that the nucleophilic addition to β-carbon is favoured when in the transoid conformation. Keywords: conformation, charge distribution, fluoronitrosoethylenes, nitrosoethylenes.

The bond orders of alternant hydrocarbon molecules

1955 ◽  
Vol 229 (1177) ◽  
pp. 251-259 ◽  
Keyword(s):  
Molecular Orbitals ◽  
Bond Orders ◽  
Hydrocarbon Molecule ◽  
Simple Interpretation ◽  
Consistent Field ◽  
Alternant Hydrocarbon ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Hydrocarbon Molecules

The equations which determine the molecular orbitals of an alternant hydrocarbon molecule are discussed. It is proved that the bond orders can be calculated algebraically by various methods without solving the eigenvalue equations. In particular, it is possible to express the bond orders as the sum of a converging series of matrices each of whose terms has a simple interpretation. The naphthalene and benzpyrene molecules are used as illustrations of the various methods. These methods are particularly useful when applied to self-consistent field treatments of these molecules.

scholarly journals Electronic Structure of Cubane-Like Vanadium–Nitrogen Cationic Clusters [V4N4]+ and [V6N6]+

Inorganics ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 52
Author(s):  
He ◽  
Zhang ◽  
McGrady
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Mass Spectrometric ◽  
Bond Orders ◽  
Functional Theory ◽  
Complete Active Space ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field

Density Functional Theory and Complete Active Space Self-Consistent Field (CASSCF) methodologies are used to explore the electronic structure of the cationic V–N clusters, [V4N4]+ and [V6N6]+, that have been identified in recent mass spectrometric experiments. Our calculations indicate that both clusters are based on cubane-like fragments of the rock-salt lattice. In the smaller [V4N4]+ cluster, the V–V bonding is delocalized over the tetrahedron, with net bond orders of 1/3 per V–V bond. In [V6N6]+, in contrast, the V–V bonding is strongly localized in the central V2N2 unit, which has a short V=V double bond. CASSCF calculations reveal that both localized and delocalized V–V bonds are highly multi-configurational.

Die Reaktivitäten des Porphins, Chlorins, Bacteriochlorins und Phlorins. Ladungsdichten, Freie Valenzen und Außenelektronendichten / The Reactivities of Porphin, Chlorin, Bacteriochlorin, and Phlorin. Electron Densities, Free Valences and Frontier Orbital Densities

1970 ◽  
Vol 25 (7) ◽  
pp. 729-734 ◽  
Author(s):  
J. V. Knop ◽  
J.-H. Fuhrhop
Keyword(s):  
Bond Orders ◽  
Frontier Orbital ◽  
Electron Densities ◽  
Reactivity Indices ◽  
Consistent Field ◽  
Self Consistent ◽  
Self Consistent Field ◽  
Frontier Orbital Model ◽  
Scf Calculations

The π-electron densities, bond orders, free valences, and reactivity indices according to Fukui's “frontier orbital”-model were calculated for all reactive centers of porphin, chlorin, bacteriochlorin and phlorin by means of Self Consistent Field (SCF) calculations using the approxima tiaons of Pariser, Parr, and Pople. The results were compared with known experimental facts. The relative reactivities of different reactivity centers (e. g. methine-bridges and β-pyrrolic carbon atoms) are well predicted by calculated π-electron densities, whereas the characteristics of similar reactivity centers (e. g. the different methine-bridges in chlorin) are better reflected in the reactivity indices of the “frontier orbital’ model. Reasons for the partial inadequacies of the models used are shortly discussed.

Self-Consistent Field Calculations of X-Ray Emission Spectra of Surface Adsorbates and Polymers

1997 ◽  
Vol 7 (C2) ◽  
pp. C2-515-C2-516
Author(s):  
H. Agren ◽  
L. G.M. Pettersson ◽  
V. Carravetta ◽  
Y. Luo ◽  
L. Yang ◽  
...  
Keyword(s):  
Emission Spectra ◽  
X Ray ◽  
Consistent Field ◽  
Self Consistent ◽  
Surface Adsorbates ◽  
Self Consistent Field

A First Principles Approach for Partitioning Linear Response Properties into Additive and Cooperative Contributions

2018 ◽  
Author(s):  
Daniel Lambrecht ◽  
Eric Berquist
Keyword(s):  
First Principles ◽  
Linear Response ◽  
Building Blocks ◽  
Field Method ◽  
Response Property ◽  
Response Properties ◽  
Consistent Field ◽  
Molecular Building Blocks ◽  
Self Consistent ◽  
Self Consistent Field

We present a first principles approach for decomposing molecular linear response properties into orthogonal (additive) plus non-orthogonal/cooperative contributions. This approach enables one to 1) identify the contributions of molecular building blocks like functional groups or monomer units to a given response property and 2) quantify cooperativity between these contributions. In analogy to the self consistent field method for molecular interactions, SCF(MI), we term our approach LR(MI). The theory, implementation and pilot data are described in detail in the manuscript and supporting information.

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