Molecular orbital index

R.L. Lopez de Compadre et al., The role of hydrophobicity in the Ames test. The correlation of the mutagenicity of nitropolycyclic hydrocarbons with partition coefficients and molecular orbital indexes. Ini. J. Quantum Chem. 34, 91-101 (1988). 

Tuppurainen K, Lotjonen S, Laatikainen R, Vartiainen T, Maran U, Strandberg M, Tamm T. About the mutagenicity of chlorine-substituted furanones and halopropenals. A QSAR study using molecular orbital indexes. Mutat Res 1991 247 97-102. 

Two different bonding indiees will be used in this book, namely bond-number and bond-order. The bond number refers to the number of pairs of electrons that form a covalent bond. It may be calculated from the weights of the valence-bond structures that are used to describe the electronic structure of the molecule, as is demonstrated above for N2O. The bond-order is a molecular orbital index of bonding. For the purpose of qualitative discussion of diatomic bonding, we shall define the bond-order to be /4 (No. of bonding electrons) - (No. of antibonding electrons). Another definition of bond-order will be introduced in Chapter 14. 

You can use Lhe senii-empineal an tl ab initio Orbuals dialog box in IlyperChem Lo ret iies[ a con Lour ploL of any molecular orbital. When req nested, lhe orbital is con toured for a plane that is parallel lo lhe screen and which is specified by a subset selection and a plane offset, as described above. The index of the orbilal and its orbilal energy (in electron volts, eV) appears in the stains line. 

In addition to the above prescriptions, many other quantities such as solution phase ionization potentials (IPs) [15], nuclear magnetic resonance (NMR) chemical shifts and IR absorption frequencies [16-18], charge decompositions [19], lowest unoccupied molecular orbital (LUMO) energies [20-23], IPs [24], redox potentials [25], high-performance liquid chromatography (HPLC) [26], solid-state syntheses [27], Ke values [28], isoelectrophilic windows [29], and the harmonic oscillator models of the aromaticity (HOMA) index [30], have been proposed in the literature to understand the electrophilic and nucleophilic characteristics of chemical systems. 

As the logarithm of 1-octanol-water partition coefficient (log P) describes the hydrophobicity of molecules and the retention of solutes in RP-HPLC depends on the hydrophobicity, a strong correlation can be expected between the log V value and the retention of solutes in RP-HPLC. Besides log P, a considerable number of physicochemical parameters have been tested for their capacity to predict retention in RP-HPLC. Thus, Snyder s polarity index, fraction of positively and negatively charged surface area, molecular bulkiness, nonpolar surface area, electron donor and acceptor capacity, various ster-ical parameters, and the energy of highest occupied molecular orbit have all been included in QSRR calculations. 

Graphical Models are introduced and illustrated in Chapter 4. Among other quantities, these include models for presentation and interpretation of electron distributions and electrostatic potentials as well as for the molecular orbitals themselves. Property maps, which typically combine the electron density (representing overall molecular size and shape) with the electrostatic potential, the local ionization potential, the spin density, or with the value of a particular molecular orbital (representing a property or a reactivity index where it can be accessed) are introduced and illustrated. 

The first mixed derivative is the Fukui function f(r) [28], a frontier molecular orbital reactivity index ... 

The summation index k now runs over all spatial molecular orbitals. 

Contents Quantum Mechanics and Atomic Theory. - Simple Molecular Orbital Theory. -Structural Applications of Molecular Orbital Theory. - Electronic Spectra and Magnetic Properties of Inorganic Compounds. - Alternative Methods and Concepts. - Mechanism and Reactivity. - Descriptive Chemistry. - Physical and Spectroscopic Methods. - Appendices. -Subject Index. 

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