Topological effect on MO energies, IV. The total ?-electron energy ofS- andT-isomers

1984 ◽  
Vol 115 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Ante Graovac ◽  
Ivan Gutman ◽  
Oskar E. Polansky
Keyword(s):  
Electron Energy ◽  
Total Electron ◽  
Total Electron Energy ◽  
Topological Effect

Bounds for the total ?-electron energy

2002 ◽  
Vol 88 (3) ◽  
pp. 317-330 ◽  
Author(s):  
Daniel A. Morales
Keyword(s):  
Electron Energy ◽  
Total Electron ◽  
Total Electron Energy

scholarly journals Dependence of the total -electron energy on large number of non-bonding molecular orbitals

2004 ◽  
Vol 69 (10) ◽  
pp. 777-782 ◽  
Author(s):  
Ivan Gutman ◽  
Dragan Stevanovic ◽  
Slavko Radenkovic ◽  
Svetlana Milosavljevic ◽  
Natasa Cmiljanovic
Keyword(s):  
Electron Energy ◽  
Molecular Orbitals ◽  
Total Electron ◽  
Total Electron Energy

Using a recently developed method for computing the effect of non-bonding molecular orbitals (NBMOs) on the total ?-electron energy (E), it was found that the dependence of E on the number n0 of NBMOs is almost perfectly linear. We now show that this regularity remains valid for very large values of n0, in particular, to hold up to n0 = 20.

A topological index for the total?-electron energy

1975 ◽  
Vol 38 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Haruo Hosoya ◽  
Kikuko Hosoi ◽  
Ivan Gutman
Keyword(s):  
Electron Energy ◽  
Topological Index ◽  
Total Electron ◽  
Total Electron Energy

scholarly journals Tripartite graphs with energy aggregation

2019 ◽  
Vol 38 (7) ◽  
pp. 149-167 ◽  
Author(s):  
Nawras A. Alawn ◽  
Nadia M. G. Al-Saidi ◽  
Rashed T. Rasheed
Keyword(s):  
Electron Energy ◽  
Degree Sequence ◽  
Maximum Energy ◽  
Chemical Components ◽  
Research Attention ◽  
Total Electron ◽  
Tripartite Graph ◽  
Total Electron Energy ◽  
Irregular Graphs ◽  
Tripartite Graphs

The aggregate of the absolute values of the graph eigenvalues is called the energy of a graph. It is used to approximate the total _-electron energy of molecules. Thus, finding a new mechanism to calculate the total energy of some graphs is a challenge; it has received a lot of research attention. We study the eigenvalues of a complete tripartite graph Ti,i,n−2i , for n _ 4, based on the adjacency, Laplacian, and signless Laplacian matrices. In terms of the degree sequence, the extreme eigenvalues of the irregular graphs energy are found to characterize the component with the maximum energy. The chemical HMO approach is particularly successful in the case of the total _-electron energy. We showed that some chemical components are equienergetic with the tripartite graph. This discovering helps easily to derive the HMO for most of these components despite their different structures.

scholarly journals Stability order of isomeric benzenoid hydrocarbons and Kekulé structure count

2009 ◽  
Vol 74 (2) ◽  
pp. 155-158 ◽  
Author(s):  
Slavko Radenkovic ◽  
Ivan Gutman
Keyword(s):  
Electron Energy ◽  
Thermodynamic Stability ◽  
Anomalous Behavior ◽  
Kekulé Structure ◽  
Benzenoid Hydrocarbons ◽  
Total Electron ◽  
Total Electron Energy ◽  
Structure Count ◽  
Resonance Energies ◽  
Stability Order

The commonly accepted opinion that the thermodynamic stability of isomeric benzenoid hydrocarbons (assessed by their total ?-electron energy and various resonance energies) increases with increasing number of Kekul? structures is shown to be violated in numerous cases. The smallest examples of such anomalous behavior are two hexacyclic pericondensed benzenoids of formula C24H14 and several pairs of heptacyclic catacondensed benzenoids of formula C30H18.

scholarly journals The Hückel total π-electron energy puzzle

2006 ◽  
Vol 71 (7) ◽  
pp. 771-783 ◽  
Author(s):  
Miljenko Peric ◽  
Ivan Gutman ◽  
Jelena Radic-Peric
Keyword(s):  
Electron Energy ◽  
Good Description ◽  
Thermodynamic Characteristics ◽  
Enthalpies Of Formation ◽  
Quantum Mechanical ◽  
Conjugated Molecules ◽  
Total Electron ◽  
Total Electron Energy ◽  
Experimental Findings ◽  
Conjugated Compounds

In spite of being based on drastic simplifications, the H?ckel molecular orbital (HMO) quantum-mechanical model provides a reasonably good description of the properties of ?-electrons in conjugated molecules. The HMO approach is found to be particularly successful in the case of the total ?-electron energy (E), by means of which it is possible to calculate enthalpies of formation and similar thermodynamic characteristics of conjugated compounds. In this paper it is shown that expressions equivalent to E can be deduced within much more accurate quantum mechanical considerations. This might explain why E agrees so well with experimental findings.

scholarly journals Iterative estimation of total π-electron energy

2005 ◽  
Vol 70 (10) ◽  
pp. 1193-1197 ◽  
Author(s):  
Lemi Türker ◽  
Ivan Gutman
Keyword(s):  
Lower Bound ◽  
Electron Energy ◽  
Upper Bound ◽  
Upper Bounds ◽  
Lower And Upper Bounds ◽  
Benzenoid Hydrocarbons ◽  
Total Electron ◽  
Iterative Estimation ◽  
Total Electron Energy ◽  
Almost All

In this work, the lower and upper bounds for total ?-electron energy (E) was studied. A method is presented, by means of which, starting with a lower bound EL and an upper bound EU for E, a sequence of auxiliary quantities E0 E1, E2,? is computed, such that E0 = EL, E0 < E1 < E2 < ?, and E = EU. Therefore, an integer k exists, such that Ek E < Ek+1. If the estimates EL and EU are of the McClelland type, then k is called the McClelland number. For almost all benzenoid hydrocarbons, k = 3.

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