Franz Werner Müller

COMBINED HIGH RESOLUTION INFRARED AND MICROWAVE STUDY OF BROMOCHLOROFLUOROMETHANE

We report a detailed spectroscopic investigation of the chiral molecule bromochlorofluoromethane (CHBrClF) with rotational resolution using a pulsed nozzle beam Fourier transform microwave (FTMW) and a waveguide FTMW spectrometer as well as a supersonic jet interferometric Fourier transform infrared (FTIR) and infrared diode laser spectrometer. The rotational spectrum of CHBrClF has been measured between 8 and 18 GHz. The quadrupole hyperfine components have been fully resolved for the assigned rotational transitions with J⩽18. Three ground state rotational constants, five centrifugal distortion constants, and all five independent elements of the bromine and chlorine quadrupole coupling tensors have been determined for each of the four isotopomers CH79Br35CIF, CH81Br35CIF, CH79Br37CIF, and CH81Br37CIF from about 500 measured transition frequencies of the hyperfine components. The quadrupole coupling tensor has been transformed to its principal axes. The determinable sign combinations of the off-diagonal e...

Einfluß von Weichmachern auf die Löschung der Lumineszenz von Pyronin B in Polymerfilmen

Den polymeren, transparente Schichten ergebenden Bindemitteln Cellulosediacetat und Polyvinylalkohol wurden verschiedene Weichmacher zugesetzt, um spezifische konzentrationsabhangige Wechselwirkungen zwischen Polymerem und Weichmacher zu analysieren. Als Untersuchungsmethode dient dabei die Verfolgung der Loschung der verzogerten Fluoreszenz der Sonde Pyronin B in diesen Polymerfilmen. Es wird gezeigt, das kleine Weichmacherkonzentrationen die Matrix verfestigen und damit beispielsweise die Sauerstoffpermeabilitat einschranken. Dieser Effekt ist besonders in Cellulosediacetat ausgepragt, fur einige Weichmacher bis in den Bereich von 30%. The effects of several plasticizers in layer-forming polymeric compounds are determined by means of the delayed fluorescence of Pyronine B to analyse the interactions between the plasticizers and polymers. It was found that small concentrations of the plasticizers harden the polymeric layers, with which, for instance, the oxygen permeability decreases. This phenomenon is marked especially for cellulose diacetate, for some plasticizers up to 30%.

Matrix effects in erythrosine sensitized photolysis of diazo compounds

Investigations have been made on erythrosine sensitized photolysis of 4-diethylaminobenzene diazonium salt 1 and 2-diazo-1-oxo-1,2-dihydronaphthalene 2 in polymeric binders of different glass transition temperatures (Tg 30–185°C). In the case of 1 the efficiency of photolysis as well as the quenching of direct and delayed fluorescence increase with decreasing Tg; in the case of 2, however, they increase with increasing Tg. The addition of plasticizers causes analogous effects. It is assumed that the sensitization of 1 occurs preferentially from the S1-state, whilst in case of 2 it is from the T1-state of erythrosine. Probability calculations reveal that the effective concentrations of the reactants within the critical radius of electron transfer are low, accounting for the low efficiency of the sensitized photolysis.