Lifetime measurements in the Fe I spectrum using tunable dye laser excitation

Radiative lifetimes of single fine structure levels of the multiplets 3d⁶ 4s(a⁶ D)4p z⁵ D ⁰ and 3d⁷ (a⁴ F)4py ⁵F⁰ of the FeI spectrum were measured. The different levels were excited by a tunable dye laser which was pumped by a pulsed nitrogen laser. The exponential decay of the fluorescence was measured directly.     

The hyperfine structure of they 8 p-multiplet of 4f 7(8 S) 6s 6p in EuI

The hyperfine splitting constants of the 4f ⁷ 6s 6p y ⁸ P _7/2 level of Eul were determined using the level crossing method. These values and those for the hyperfine splittings of the other 4f ⁷ 6s 6p levels are compared to theoretical values calculated with eigenfunctions of Smith and Collins. For the quadrupole coupling constants a better agreement between theory and experiment is obtained if different 〈r ^?3〉 _p -parameters are assumed for 4f(⁸ S) 6s 6p(³ P) and for 4f ⁷(⁸ S) 6s 6p(¹ P).     

Die relative Isotopenlage des Os186

Using three different samples of Os¹⁹², Os¹⁹⁰ and Os¹⁸⁶ enriched to 98.68%, 95.46%, and 61.27%, respectively, the isotopic shiftsΔν(Os¹⁹²?Os¹⁹⁰) andΔν(Os¹⁹²?Os¹⁸⁶) have been measured in four Os I-lines with a recording Fabry-Perot spectrometer. The relative isotopic position of Os¹⁸⁶ has been found to be

$$\frac{{\Delta \nu (Os^{192} - Os^{186} )}}{{\Delta \nu (Os^{192} - Os^{190} )}} = 3.52 \pm 0.03.$$     

Experimente mit Erdalkaliatomen in metastabilen Zuständen

An atomic beam source for atoms in metastable states is described. The source was used to produce metastable Ca and Sr atoms in the³ P _0,1,2 and¹ D ₂ and Mg atoms in the³ P _0,1,2 states. The population of these levels was high enough (about 30% of the atoms were in the³ P levels and 3% in the¹ D ₂ level) so that zero field level crossing experiments could be performed at highly excited levels which were populated by an optical excitation starting from the metastable states. The lifetime results obtained for Ca areτ(4s 4d ³ D ₁)=(1.21±0.07)·10^?8sec,τ(4s 4f¹ F ₃)=(2.84±0.23)· 10^?8sec, andτ(3d 4p ¹ F ₃)=(6.15±0.62)·10^?8 sec. The three lifetimes have been evaluated using theg _J values forLS-coupling. The quoted uncertainties include the errors by a possible deviation fromLS-coupling.     

Optical resolution beyond the natural linewidth: A level-crossing experiment on the 32 P 3/2 level of sodium using a tunable dye laser

A level crossing experiment on the hyperfine structure of the 3² P _3/2 level of Na²³ was performed using a nitrogen laser pumped dye laser for the excitation of the Na atoms. The fluorescent light was observed in time intervals which were initiated up to seven lifetimes after excitation. Therefore the signal was only determined by atoms having survived in the excited state up to the initiating time. The minimum linewidth observed was 6 times smaller than the natural width. Neighbouring crossing signals, which overlap in a level crossing experiment using time integral observation of the fluorescent light, could be resolved. The accuracy of the hyperfine constants of the 3² P _3/2 level could be improved.     

Elektrochemische Untersuchungen an Organothallium(III)-Verbindungen

The electrochemical reduction of dialkylthallium(III) cations in aqueus buffer solutions and dimethylformamide yields by the first electron transfer the instable intermediate {R₂Tl}, which in dependence of the reaction conditions is electrochemical reduced to Tl° or disproportionates to R₃Tl and Tl°. Phenyl-substituted organothallium compounds are reduced to Tl° and (C₆H₅)₂Hg in one step.     

Determination of the deuterium abundance in water using a cw chemical DF laser

This paper describes a new method for the determination of the deuterium content in water samples. The absorption of the radiation of a cw deuterium fluoride laser by HDO in water vapor is measured by means of a nonresonant spectrophone (optoacoustic detector). This method enables one to evaluate the isotope ratio of hydrogen in a rather simple and straightforward way. Advantage is taken of the fact that HDO absorbs some of the DF laser lines whereas H₂O shows no absorption. Due to the small concentration in natural water deuterium is practically entirely present as HDO. Therefore a selective determination of the deuterium content is possible. In the course of the investigation the absorption coefficients of HDO for the different laser lines were determined. It was thereby established that there exists a strong coincidence of an HDO absorption line with the 2P2 DF laser line. The detection sensitivity of the method was then examined for some selected laser lines. The concentration of HDO in natural water samples could be determined with an accuracy of better than 10%. The experiments, however, show that with appropriate improvements it should be possible to achieve an accuracy of better than 1%. This makes the method very interesting as an analytical tool in hydrology.     

Measurement of frequency differences between visible laser lines up to 170GHz using metal-insulator-metal point contact diodes

Frequency differences of up to 170 GHz between a cw dye laser and a krypton laser at 568 nm were measured by mixing laser and microware radiation with a metalinsulator-metal point contact diode. Beat signals are well above noise and there is still great potential for improvement when better microwave oscillators are used. From the measurements reported it follows that the diode can be used for determining still higher frequency differences of visible laser radiation.     

Die Harmonischen der Rotationsenergie bei der Schubkurbel und verwandte Fourier-Reihen

Summary The rotational energy of a link in a mechanism is proportional to the square of its angular velocity. This square, in contrast to the angular velocity itself, can be expanded into a Fourier series, having finite values for its coefficients. The problem is solved by splitting it into partial fractions, leading to the harmonic analysis of the slotted lever mechanism. Further related series are given at the end.