NOPR Collection:

A study of molecular Rydberg transitions of monofIuoroethylene and difluoroethylenes

Wed, 01 Sep 1993 00:00:00 GMT

Title: A study of molecular Rydberg transitions of monofIuoroethylene and difluoroethylenes Authors: Joshi, B A; Chhaya, V M; Chhag, Smita Abstract: Molecular Rydberg transition of monofluoroethylene and difluoroethylenes has been studied employing RINDO (Rydberg Intermediate Neglect of Differential Overlap) method. Koopmans ionization potential and valence as well as Rydberg excitation band energies are calculated. These include singlet-singlet and singlet-triplet transition as well as singlet-triplet splitting energies. The results are compared with earlier theoretical and experimental results. The present singlet-triplet transitions (π→ π*) energies are very close to the experimental results. Singlet-singlet transition (π→ π*) also give good agreement with the experimental results. Page(s): 743-748

New experimental findings in two-dimensional fractal-like, dendritic and periodic growth of KCI in dense matrices

Wed, 01 Sep 1993 00:00:00 GMT

Title: New experimental findings in two-dimensional fractal-like, dendritic and periodic growth of KCI in dense matrices Authors: Rastogi, R P; Das, Ishwar; Jaiswal, Kiran; Chand, Sudha Abstract: Fractal-like, dendritic and periodic morphologies have been observed experimentally in thin films of KCI solution containing a denser matrix such as agar- agar or polyvinyl alcohol polymer. In the case of fractal-like structures, calculated values of fractal dimensions are in good agreement with two-dimensional diffusion limited aggregation (DLA) model. A transition like behaviour from fractal type to dendritic growth with increase in KCI concentration has been observed. Dendritic form is always found to be favoured when KCI content is high in comparison to the case when KCI content is low. In the case of dendritic growth, length of the crystal (d) increases linearly with time (t) obeying the equation d = mt + C, where the values of slope (m) and the intercept (C) depend on electrolyte concentration. In the case of periodic growth patterns, band locations (Xn) have been plotted as a function of band number n and the plots obey the simple relation Xn = mn + C where the values of slope m and the intercept C depend on experimental conditions. Page(s): 749-753

Spectral characteristics and in distribution of a few aromatic amines in anionic micelles

Wed, 01 Sep 1993 00:00:00 GMT

Title: Spectral characteristics and in distribution of a few aromatic amines in anionic micelles Authors: Sarpal, Ranjit S; Dogra, Sneh K Abstract: Spectral characteristics of eight aromatic amines and their monocations have been studied in sodium dodecyl sulphate (SDS) micelles. Absorption and fluorescence data indicate that the polarity of micellar site where aromatic amines bind is greater than that of acetonitrile and water molecules are present near the aromatic amine. An increase in the concentration of electrolyte decreases the polarity well as the water content present the micelles. An increase in the fluorescence quantum yield of aromatic amines in SDS micelles s compared to that in water is due to the decrease in the rates of non-radiative decay processes an is substantiated by the excited state lifetime measurements data. Binding constants of these amines to micelles increase with the increase in hydrophobicity of, the molecule. Page(s): 754-761

Homolytic displacement at saturated carbon in organocobaloximes: Part VI† - Synthesis of benzyl sulphones

Wed, 01 Sep 1993 00:00:00 GMT

Title: Homolytic displacement at saturated carbon in organocobaloximes: Part VI† - Synthesis of benzyl sulphones Authors: Gupta, B D; Das, Indira; Dixit, Yandana Abstract: The reactions of thiophene-2-sulphonyl chloride with benzyl and para-substituted benzyl cobaloximes under anaerobic and photochemical conditions at 0°C give benzyl sulphones and bibenzyls in variable yields. However, the reactions with heteroaromatic methyl cobaloximes give the corresponding sulphones as the exclusive organic products. The reactions are interpreted in terms of S_H2 mechanism. Page(s): 762-766