LASER FLASH PHOTOLYSIS OF EOSIN AND ITS COMPLEX WITH LYSOZYME

Abstract— The transient absorption spectra of aqueous solutions of eosin and of the lysozyme-eosin complex have been examined after excitation with a Q -switched frequency-doubled (347 nm) ruby laser pulse. Eosin itself gives three broad, intense short-lived absorption bands with maxima at wavelengths of 410, 460 and 580 nm, which other workers have identified with the semi-reduced and semi-oxidized radicals and the triplet state of the dye, respectively. In the complex with lysozyme, the yield and lifetime of the eosin triplet are greatly reduced in comparison with the free dye. It is suggested that excited eosin, when bound to lysozyme, decays mainly from the singlet state by pathways such as charge transfer which are not available to the free molecule.     

Aromatic polyfluoro compounds LVII [1]. Nucleophilic replacement reactions of 1, 2, 3,5-tetrafluoro-4-nitrobenzene, 1, 2, 3, 5-tetrafluorodinitrobenzene and 1-bromo- 2, 3, 4, 6-tetrafluoro-5-nitrobenzene

The title compounds have been treated with dimethylamine and sodium methoxide in polar solvents, and the isomer ratios of the products determined. Although attack para to the nitro group is in each case favoured over ortho, it is so by only surprisingly small factors. Structures have mostly been assigned spectroscopically, supported in one case by a chemical proof. The dinitrotetrafluorobenzene is activated sufficiently to react directly with methanol at 35°C, with a pseudo first order rate constant of (7±1) ×10^?5 s^?1     

Rotational analysis of the (f0, e0)-X21 transition of the antimony monofluoride molecule

A rotational analysis is performed on the 0-0 band of the so called C₂ band system of antimony monofluoride. The results show that the band actually consits of two transitions designated as the f0⁺-X₂1 and e0⁻-X₂1 transitions.     

Electron impact mass spectra of some substituted aromatic boronate derivatives of bifunctional compounds

The electron impact mass spectra of the 3,5-bis(trifluoromethyl)benzeneboronate, 2,4-dichlorobenzene-boronate and 4-bromobenzeneboronate derivatives of some bifunctional diols and aminoalcohols are characterized by prominent molecular ions with diagnostically useful modes of fragmentation. Many of the principal ions in the mass spectra retain boron in their structure.     

A mössbauer spectroscopic interpretation of some properties of organotellurium compounds

A review of Tellurium-125 Mössbauer parameters is used to explain the colour of some organatellurium compounds in terms of the population of low energy conductance bands by non bonding electrons.     

The fluorescence lifetime of tetracene vapour

The fluorescence lifetimes of tetracene vapour as a function of excess vibrational energy in the first excited singlet state have been measured under collision free conditions. A very marked decrease in lifetime with increasing energy has been observed. We attribute this behaviour to enhanced internal conversion from vibrationally excited levels.     

Electrostatic force on an earthed conducting sphere due to a dipole layer

The electrostatic force on a conducting sphere due to a dipole layer is given graphically.

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Résumé Nous obtenons graphiquement la force éléctrostatique sur une sphère conductrice située près d'une couche de dipôle.

     

Visualization of electron correlation in ground states of He and H−

For the ground states of He and H^?, conditional probability densities d(r₂,θ₁₂r₁) for finding two electrons in different relative positions have been calculated for several wavefunctions including simple one-configuration wavefunctions and Hylleraas—Kinoshita type functions. The calculations, including graphing, were all carried out on a desktop computing calculator.     

The correct McLachlan method in free radicals and radical anions

A recent modification to the McLachlan method is corrected. This modification, when correctly applied to odd alternant hydrocarbons, reproduces McLachlan's results instead of improving their agreement with experiment. The modification is irrelevant and erroneous for radical anions.