Gisbert Zu Putlitz

Two-photon laser spectroscopy of the muonium 1S–2S transition

The 12S1/2(F=1)−22S1/2(F=1) energy interval in muonium has been investigated by Doppler-free two-photon laser spectroscopy. The transition was observed by uniquely identifying and counting the muons released after the photoionization of the 2S state by the same laser field. The measured transition frequency of 2455 528016(58)(43) MHz is in good agreement with QED calculations. The experiment can be interpreted as a test of the Lamb shift contributions at the 1% level. The method is also well suited for a precise determination of the mass of the positive muon in a muoniumhydrogen isotope shift measurement.

Bestimmung des elektrischen Kernquadrupolmomentes des ungeraden stabilen Strontium-87-Kerns

AbstractIn order to determine the electric quadrupole moment of Sr87 (I= 9/2) the hyperfine structure-splitting of the 5s5p3P1-state of the SrI-spectra was investigated by optical double resonance.By detection of high frequency transitions (ΔF=±1,ΔmF=0,±1) in an external magnetic fieldH0≈0 one obtains the hyperfine structure separations asvF=11/2−F=9/2=1463·149 (6) Mc/sec andvF=9/2−F=7/2=1130·264 (6) Mc/sec.From these frequencies one calculates the magnetic hyperfine structure-splitting constantA=−260·084 (2) Mc/sec and the electric quadrupole interaction constantB=−35·658 (6) Mc/sec. B leads to an electric quadrupole moment ofQ(Sr87)=+0·36 (3)·10−24 cm2.

Investigation of impurities in superfluid Helium by optical spectroscopy

Abstract The implantation of impurity ions in liquid 4 Helium leads to the formation of pointlike defects in the quantum fluid. Optical spectroscopy contributes to the understanding of the structure of these defects and of the interaction with the superfluid phase as well. Recent experimental work was concentrated on the spectra of alkaline earth ions which show radiative transitions in contrast to the alkali elements investigated in earlier experiments.

Two-photon intracavity dye laser spectroscopy of the 4S and 3D term in6, 7Li

Doppler-free two-photon spectroscopy of several states of6, 7Li has been achieved by placing an atomic beam inside the dye laser cavity. The hyperfine structure splitting of the 4S state, the fine structure splitting of the 3D level as well as the isotope shifts of the 2S–4S and 2S-3D transition have been measured, by scanning the single-mode laser frequency and detecting the fluorescence light. In addition, signal detection by three-photon ionization via the resonant 3D state was accomplished.

First observation and mobility measurements of negative ions in superfluid 4He

We present the results of the first mobility measurements in superfluid helium for negative ions of different elements. Various negative ions like Cl-, F- and I- were produced by laser ablation from targets consisting of NaCl, NaF, NaI, LiF and KCl immersed in a He-4 bath. In addition to negative ions of halogen ablated from salts we have studied the mobility of the negative metallic ions Ba- and Ga- implanted into superfluid helium

STM studies on dye molecules embedded in ordered liquid crystal structures and an approach for laser-assisted scanning tunneling microscopy

Scanning tunneling microscopy, although capable of yielding very high resolution on periodic structures, very often provides only moderate resolution on singular features. Our work aims at the use of laser light to improve the identification of individual molecules. We report on scanning tunneling microscopy measurements performed on dye molecules dissolved in a liquid crystal and adsorbed onto highly oriented pyrolytic graphite. Either localized perturbations of the liquid crystal structure with the size of single molecules or more or less extended ordered domains of well resolved dye molecules were reproducibly imaged for several dyes. To study light-induced resonant effects the influence of non-resonant absorption leading to thermal expansion of tip and sample has to be suppressed. Therefore, an electro- optical system was realized using an ArPLU- and a dye laser of different wavelengths power-modulated with a relative phase shift of 180 degree(s). Preliminary results obtained with this setup are presented documenting the efficiency of the compensation.

Industrial foundations and society

With their inventions of two, three, and four wheeled vehicles, as well as several different types of motor, Gottlieb Daimler and Karl Benz spearheaded a technical revolution in mobility and in the availability of virtually unlimited power. Today, a century later, giant mining machines, huge engines that generate electrical power or propel supertankers, automated equipment that can build roads in a single action from flattening the soil to laying the surface, engines that fly planes over oceans and continents, and an endless stream of motorised vehicles from rickshaws to trucks all bear witness to the size and impact of this revolution.