Journal ArticleDOI
Use of the CNDO Method in Spectroscopy. III. Monosubstituted Benzenes and Pyridines
Janet E. Del Bene,H. H. Jaffé +1 more
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TLDR
In this paper, the modified CNDO method was applied to the calculation of a series of monosubstituted benzenes and pyridines and the calculated values of the transition energies and corresponding oscillator strengths were in good agreement with available experimental data on the electronic spectra of these compounds.Abstract:
The modified CNDO method previously reported has been applied to the calculation of a series of monosubstituted benzenes and pyridines, namely, aniline, anilinium ion, benzonitrile, nitrosobenzene, phenol, phenoxide ion, toluene, pyridinium ion, pyridine‐N‐oxide, 1‐hydroxy‐pyridinium ion, the aminopyridines, and the cyanopyridines. The calculated values of the transition energies and corresponding oscillator strengths are in good agreement with available experimental data on the electronic spectra of these compounds. An analysis of the lower‐energy excited states by means of the calculated results suggests that there is an astonishingly small amount of charge‐transfer character associated with the observed ultraviolet bands. The calculations indicate that the changes in charge densities in going from the ground state to the lowest energy π → π* excited state can be related to the Hammett σ's for the substituents.read more
Citations
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Journal ArticleDOI
Use of the CNDO Method in Spectroscopy. IV. Small Molecules: Spectra and Ground‐State Properties
Janet E. Del Bene,H. H. Jaffé +1 more
TL;DR: The modified CNDO method has been applied to the study of the electronic-absroption spectra of several small molecules; namely, formaldehyde, formic acid, formamide, allene, ketene, and diazomethane, with quite satisfactory results as mentioned in this paper.
Journal ArticleDOI
Competing adiabatic photoreaction channels in stilbene derivatives
Wolfgang Rettig,Wilfried Majenz +1 more
TL;DR: In this article, a stepwise relaxation model was proposed for a TICT state (twisted single-bond conformation) as the main fluorescent species and temperature-activated non-radiative decay via a photochemical funnel with twisted double-bund conformation.
Book ChapterDOI
Quantum-Mechanical Prediction of Tautomeric Equilibria
TL;DR: In this article, the scope and limitations of quantum-mechanical methods and several aspects of the tautomeric equilibria of heterocyclic compounds are discussed.
Journal ArticleDOI
Multiple relaxation pathways in photoexcited dimethylaminonitro- and dimethylaminocyano-stilbenes
TL;DR: In this paper, the photophysical behavior of para-nitro, para-cyano, and meta-nibro-4′-dimethylaminostilbenes is compared and explained.
Journal ArticleDOI
Considerations on the dipole moment of molecules forming the twisted intramolecular charge transfer state
TL;DR: In this paper, the ground and excited-state dipole moments extracted from electro-optical emission and solvatochromic measurements of dual-fluorescing dimethylaminobenzonitrile (DMABN) derivatives are compared.
References
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Journal ArticleDOI
Use of the CNDO Method in Spectroscopy. I. Benzene, Pyridine, and the Diazines
Janet E. Del Bene,H. H. Jaffé +1 more
TL;DR: In this article, the CNDO method was modified by substitution of semi-empirical Coulomb integrals similar to those used in the Pariser-Parr-Pople method, and by introducing a new empirical parameter κ to differentiate resonance integrals between σ orbitals from those between π orbitals.
Journal ArticleDOI
Use of the CNDO Method in Spectroscopy. II. Five‐Membered Rings
Janet E. Del Bene,H. H. Jaffé +1 more
TL;DR: In this paper, the modified CNDO method was used to calculate the electronic spectra of cyclopentadiene, the Cyclopentadienide ion, pyrrole, furan, pyrazole, imidazole, 2-pyrrolecarboxaldehyde, and furfural.
Journal ArticleDOI
Changes in the Electronic Transitions of Aromatic Hydrocarbons on Chemical Substitution. II. Application of Perturbation Theory to Substituted‐Benzene Spectra
TL;DR: In this article, an analysis of the changes that occur in the 2600, 2050, and 1850 A transitions of benzene on chemical substitution is presented and applied to a large collection of intensity change and frequency shift data obtained from the literature.
Journal ArticleDOI
Vacuum ultra-violet absorption spectra of various mono-substituted benzenes
K. Kimura,S. Nagakura +1 more
TL;DR: In this paper, the vacuum ultra-violet spectra of various mono-substituted benzenes were measured in the wavelength region of 1550 A to 2200 A in the vapour phase by a recording vacuum ultra violet spectrophotometer.
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