Spectroscopic calculations of CH bond dissociation energies for ethene, propene, and benzene chlorine derivatives

CH bond dissociation energies have been determined by spectroscopic and quantum-chemical calculations for ethane, propene, and benzene chlorine derivatives. The spectroscopic values of CH bond dissociation energies were obtained from the fundamental absorption bands in an anharmonic approximation using the variation method and the Morse harmonic basis. Quantum-chemical calculations were carried out using the 6-311G(3df,3pd)/B3LYP basis. The resulting tendencies of variation of bond dissociation energies are discussed in relation to changes in the structure of the molecule.     

Computational spectroscopy: status of problem

The possibility of constrution the system of artificial intelligence for processing of molecular spectroscopy data is discussed. The development of the theory of spectra and molecular structures as well as possibility to carry out sufficiently precise calculations make it possible to construct algorithmic systems operating with molecular models of different complication. The successive study of such models leads to the complete solution of inverse spectral problems. The state of the problem is considered.     

Combined method for calculating raman band intensities with consideration for the dependence of the raman tensor on the frequency of exciting radiation

It is shown that at certain assumptions the tensor of Raman bands can be represented as a sum of the Placzek term and the fast convergent series that contains information on the sensitivity of the tensor elements to the frequency of exciting radiation. The convergences of the corresponding series and the frequency dependences of the Raman band intensities for particular molecules are studied by computer experiments. Vernadskii Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences. Moscow State Civil-Engineering University. Translated fromZhurnal Strukturnoi Khimii, Vol. 37, No. 2, pp. 241–249, March–April, 1996. Translated by I. Izvekova     

Spectroscopic calculations of CH and OH bond dissociation energies for aldehydes, ketones, acids, and alcohols

CH and OH bond dissociation energies were calculated by the spectroscopic and quantum-chemical methods for aldehydes, ketones, acids, and alcohols. The spectroscopic values of CH and OH bond dissociation energies were obtained from the fundamental absorption bands by the variational method in an anharmonic approximation using the Morse-anharmonic basis set. Quantum-chemical calculations were carried out using the 6-311G(3df,3pd)/B3LYP basis set. It is discussed how the bond dissociation energies change with the structure of the molecule.     

On the problem of directed signal transmission and energy transfer in molecular systems

A new physical interpretation of the mechanism of directed energy transfer and signal transmission in molecular systems along one-dimensional chains capable of successive isomerization is proposed. The photoacceptor—transmitting chain—reaction center system is considered as a model. Conditions under which the directed energy transfer occurs from the photoacceptor to the reaction center along the chain are analyzed. The time of signal transmission depends on the chain length, and the transmission coefficient is mainly determined by the characteristics of the initial and final elements in the whole system.     

<Emphasis Type="Italic">Ab initio</Emphasis> investigation of aniline and <Emphasis Type="Italic">n</Emphasis>-propylamine associates with dimethylsulfoxide,isobutyronitrile, and N-methylpiperidone

The structure of the dimer associates of aniline and n-propylamine with dimethylsulfoxide, isobutyronitrile, and N-methylpiperidone was investigated by ab initio calculations. Stable configurations of the complexes and their structural and energy characteristics have been determined. The effects of the nature of the solvent and the structure of the associate on the properties of the NH₂ group are examined.     

On the solution of one classical problem in vibrational spectroscopy

The identification of the structure of molecules from their vibrational spectra has been considered as an inverse spectral problem. A statement of the problem has been formulated and an algorithm has been treated for its solution. Conditions for obtaining a unique solution have been analyzed. An attempt has been made to evaluate the possibility of distinguishing isomers by calculating their vibrational spectra.     

<Emphasis Type="Italic">Ab initio</Emphasis> study of aniline and <Emphasis Type="Italic">n</Emphasis>-propylamine associates with nitrobenzene and <Emphasis Type="Italic">m</Emphasis>-cresol

An ab initio (6-31G**) study of binary associates of aniline and n-propylamine with nitrobenzene and m-cresol has been carried out. The structures corresponding to the total energy minimum of the system have been found for the associates, and their geometrical and energy characteristics have been determined. Basic types of intermolecular interactions have been established, and their effects on the reactivity of the amino group have been investigated.Original Russian Text Copyright © 2004 by I. A. Novakov, V. V. Korolkov, A. I. Pavlyuchko, B. S. Orlinson, and L. A. GribovTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 4, pp. 595–601, July–August, 2004.This revised version was published online in April 2005 with a corrected cover date.