Ultrafast spectroscopy of the solvent dependence of electron transfer in a perylenebisimide dimer

We investigate the photoinduced intramolecular electron-transfer (IET) behavior of a perylenebisimide dimer in a variety of solvents using femtosecond transient absorption spectroscopy. Overlapping photoinduced absorptions and stimulated emission give rise to complicated traces, but they are well fit with a simple kinetic model. IET rates were found to depend heavily on solvent dielectric constant. Good quantitative agreement with rates derived from fluorescence quantum yield and time-resolved fluorescence measurements was found for forward electron transfer and charge recombination rates.     

Acylaluminum dichlorides

Evidence has been obtained for the formation of acylaluminium dichlorides by transmetalation between Cp₂Zr(Cl)(acyl) and AlCl₃. They have been shown to be reactive toward electrophiles at both the carbon and the oxygen of the acyl group.     

Circular carrier-frequency photography for observing phase objects

A circular grating is photographed through a phase object which deforms the image of the grating lines. By super-imposing these deformed lines with a master grating on photographic film, moiré patterns are observed. These patterns are interpreted as fringes of constant radial derivative.     

Induced rotational effects in relativity

Using the Kerr metric the angular velocity of the locally nonrotating frame (LNRF) shell is shown to be equal to the value obtained by Thirring. It is established that perfect dragging as seen by a distant observer occurs when the red shift becomes infinite, while no such effect is observed in the LNRF.The work in this paper was commenced while the author was at the Department of Mathematics, University of Sri Lanka Peradeniya Campus, Sri Lanka.     

Complexes amines du rhodium(I) : I. Complexes du type chloro-monoamine cyclooctadiène- 1,5 rhodium(I) et leurs produits de réaction avec l''oxyde de carbone

The reaction of amines with [(RhClCod)₂] (Cod = 1,5-cyclooctadiene) gives monomeric compounds [RhCl(Am)Cod](Am = amine). Elementary analyses as well as IR and NMR spectra are consistent with their structure.On treatment with carbon monoxide at atmospheric pressure these compounds give a series of complexes, [RhCl(Am)(CO)₂], identified by elementary analyses and IR spectra.The thermolysis of [RhCl(Aam)(CO)₂] with Aam = allyamine gives [{RhCl(Aam)CO_n}] not perfectly isolated. The reaction of [{RhCl(CO)₂}₂] with 2-vinylpyridine leads to the same kind of compound [{RhCl(Vpy)CO_m}] with Vpy = 2 -vinylpyridine. This latter complex is identified by elementary analysis. The IR spectra of these two complexes show that the olefinic double bond of amines β,γ-insaturated interacts with a rhodium atom. Their properties are discussed.     

Mathematical programming methods for the optimal design of turbine blade shapes

This paper describes some optimization techniques for the design of turbine blade profiles with a vibration constraint. The vibration characteristics were modelled by a Timoshenko beam with idealized boundary conditions permitting the system dynamics to be simulated by differential equations. Elliptical cross-sectional shapes were assumed, resulting in an optimization problem in a finite number of variables. The methods used were (1) a direct handling of the differential equations describing the system, in which penalty function transformations were used, and (2) a finite difference discretization with the system equations replaced by finite difference approximations. In the latter formulation the vibrational frequencies are the eigenvalues of the system while in the former case they are regarded as control parameters.This paper includes a numerical study of these methods and their implementation together with a discussion of results.     

Les séries de multipôles des physiciens et la théorie des ultradistributions

Sans résuméÀ MonsieurGottfried Köthe, à l'occasion de son 60^me anniversaire