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1

Molecular Orbital Studies on Electronic Spectra of Some Substituted Anthraquinone Cation Radicals

100%

Armed M., Khan Z.

Acta Physica Polonica A

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1995

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vol. 87

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issue 6

939-951

EN

Electronic transition energies of radical cations of some hydroxy-substituted anthraquinones are calculated using an open-shell self-consistent field method with limited configuration interaction. The results are analyzed and a correlation diagram is given which provides useful information about the characteristic behaviour of the electronic transitions depending on the positions of the hydroxyl substituents. Also, the first ionization potentials of substituted anthraquinones are calculated using an empirical relation connecting ionization potentials with the lowest-energy non-Koopmans bands for their radical cations. Such information is particularly useful for systems like substituted anthraquinones for which uv photoelectron spectroscopic data are in scarce.

2

Open-Shell SCF-CI Calculations for Radical Cations of Dihydroxynaphthalenes with C_{2v} and C_{2h} Symmetry

100%

Khan Z.

Acta Physica Polonica A

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1991

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vol. 80

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issue 1

29-45

EN

Electronic spectra of radical cations of dihydroxynaphthalenes with C_{2v} and C_{2h} symmetry are calculated using an open-shell SCF method with configuration interaction (CI). The characteristic behaviour of electronic transitions depending on the positions of the hydroxyl substituents is discussed. An interesting aspect of this work is the estimation of the first ionization potentials (IP's) of neutral dihydroxynaphthalenes from the energy of the lowest non-Koopmans state for their radical cations. This method for the prediction of IP's is found to be at least as good as that of the Koopmans' theorem with energy correction due to bond perturbation.

3

Simple Model Description of Chemical Reactivity and Reaction Pathways

100%

Brocławik E.

Acta Physica Polonica A

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1991

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vol. 79

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issue 5

627-634

EN

Simple model of preliminary selection of possible reaction pathways for the reaction between multiatomic molecules is proposed. Most probable directions of the attack are estimated from plots of the total energy gradient as a function of mutual orientation of reacting molecules for large intermolecular distances. The method is verified for the oxidation reactions of ethylene and amidogen and also for amidogen interaction with NO. The possibility of the application of the proposed method to catalytic reactions is discussed.

4

Electronic Spectra of Radical Cations and their Correlation with Photoelectron Spectra. VI. A Reinvestigation of Two-, Three-, and Four-Ring Condensed Aromatics

51%

Khan Z.

Acta Physica Polonica A

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1992

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vol. 82

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issue 6

937-955

EN

Earlier interpretations of the electronic spectra of two-, three-, and four-ring condensed aromatic hydrocarbon radical cations are reexamined in the light of the UV photoelectron spectroscopic data for their neutral precursors and improved open-shell self-consistent field configuration interaction (SCF-CI) calculations. From the electronic transition energies for some 33 aromatic radical cations obtained from electronic absorption spectra (EAS) and those inferred from photoelectron spectra (PES), the following correlation is found between the two types of spectroscopies: E_{EAS} = (0.23 ± 0.20) + (0.98 ± 0.01)E_{PES}. The slope of this line is very close to unity which shows that the matrix shift on going from the solid phase (electronic spectrum) to the vapour phase (PE spectrum) is almost negligible and that there is no appreciable change in the geometry of the molecules on ionization.

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4 Acta Physica Polonica A

1 1995

1 1992

2 1991

3 Khan Z.

1 Armed M.

1 Brocławik E.

Molecular Orbital Studies on Electronic Spectra of Some Substituted Anthraquinone Cation Radicals

Open-Shell SCF-CI Calculations for Radical Cations of Dihydroxynaphthalenes with C_{2v} and C_{2h} Symmetry

Simple Model Description of Chemical Reactivity and Reaction Pathways

Electronic Spectra of Radical Cations and their Correlation with Photoelectron Spectra. VI. A Reinvestigation of Two-, Three-, and Four-Ring Condensed Aromatics