Schwingungsanregung von H2-Molekülen durch Zentralstoß mit Li+-Ionen

An apparatus is described for measuring the inelastic differential cross section for vibrational excitation in collisions of diatomic molecules with monoenergetic ions at laboratory energies between 10 and 50 eV. The method consists of measuring the time of flight of single ions with a time amplitude converter and displaying the results on a 100 channel pulse height analyzer. From the shift in the time of flight relative to that expected for elastic scattering the final state of the molecule excited in a single collision is identified. By studying only central collisions with almost zero impact parameter rotational excitation is strongly suppressed. Measured times of flight after collisions of monoenergetic Li⁺ ions with H₂ show that with increasing energy the most probable vibrational quantum jump increases from 0→1 to 0→2,0→3 etc. Contrary to the usual assumption of a small steric factor for vibrational excitation the results show that the inelastic cross section is larger than the elastic cross section. Using reported potential parameters the energy dependence of the most probable excited state is compared with the calculations of Secrest and Johnson for a one-dimensional collinear collision. The satisfactory agreement suggests that the steric factor is close to 1. From measurements at different scattering angles at 10 eV the integral inelastic cross section is found to be about 0.2 Ų corresponding to a differential cross section of 0.4 Ų/sr. Measured values of integral and differential total cross sections for Li⁺-He andLi⁺-H₂ are reported and compared with theory. Direct dissociation of D₂ by Li⁺ in the energy range from 25 to 55 eV was not observed, yielding an upper limit for the cross section of 4 · 10^?4 Ų/sr.     

Optimale Bedingungen für die Gewinnung von radioaktivem Tabakmosaikvirus

Zusammenfassung Mit Tabakmosaikvirus infizierte Blätter wurden während 24 Stdn. zur Assimilation von radioaktivem Kohlendioxyd veranlaßt. Virus höchster spezifischer Radioaktivität wurde erhalten, wenn die Blätter kurz nach der Infektion dieser Radiophotosynthese unterworfen wurden; höchste Gesamtaktivität ergab sich bei Radiophotosynthese mindestens einen Monat nach Infektion. Ein beträchtlicher Teil der Aktivität befand sich im Nukleinsäureteil des Moleküls. Durch Infiltration von infizierten Blättern mit Radioglukose und nachfolgende Aufbewahrung im Dunkeln ergab sich ebenfalls radioaktives Virus; der Einbau des Radiokohlenstoffes in das Virus ist also nicht notwendig mit der Photosynthese gekoppelt.     

On a variational-perturbational method for large perturbations

Using a perturbation theoretical argument an effective variational ansatz for the ground state is given. The formula works for arbitrary coupling strengths. The anharmonic oscillator is presented as an example and a comparison with other methods is made.     

Kinetic-catalytic determination of vanadium in non-aqueous solvents

Determination of trace vanadium in organic solvents is studied by use of the oxidation of o-dianisdine with t-butyl hydroperoxide. The sensitivity of the catalyzed reaction is optimized by application of a modified simplex method. Under optimum conditions the detection limit is 0.7 ng V ml^?1 in acetonitrile and the relative standard deviation is 0.048. The effect of other metal ions and of co-solvents is discussed. The method is used for trace determinations of vanadium in organic solvents of high purity.     

Eikonal and Fresnel corrections to the Glauber theory of nuclear multiple scattering

Starting from a Watson-type multiple scattering series we study first-order corrections to the Glauber high-energy collision model. These are obtained by replacing the free-space Green function between successive scatterings by the second-order eikonal propagator. We distinguish between Fresnel corrections and eikonal-type corrections. Due to large cancellation effects the eikonal contribution is very small compared to the Fresnel contribution. First-order corrections to Glauber theory are calculated explicitly for high-energy elastic scattering of protons from light nuclei (⁴He, ¹²C, ¹⁶O).     

Phase-matched third-harmonic generation in dye solutions

Various dyes are investigated for their capability of generating 3^rd harmonic of Nd-laser light. The feasibility of achieving phase matching is demonstrated by direct measurements of the index of refraction. Third-harmonic conversion of hexamethylindocarbocyanine iodide, diethyloxacarbocyanine iodide and fuchsin red are compared. The highest conversion is obtained for hexamethylindocarbocyanine iodide (80 times higher than in fuchsin red). A further enhancement of the third harmonic by a factor of 70 is expected for the fundamental laser light at 1.15 μm.     

5,6-Dihydro-1,4-thiazine durch Einwirkung von Propylenimin auf α-Mercaptoketone

Zusammenfassung Die Umsetzung von -Mercaptoketonen mit Propylenimin führt zu 2,3-disubstituierten 5-Methyl-5,6-dihydro-4H-(bzw. 2H)-1,4-thiazinen. Sie reagieren im Gegensatz zu den in Stellung 5 nicht substituierten Äthylenimin-Reaktionsprodukten nicht mit einem weiteren Mol--Mercaptoketon unter Bildung von Thiazolo[2,3-c]-1,4-thiazinen.Die Dihydrothiazine lassen sich mit Ameisensäure oder NaBH₄ zu sterisch identischen Thiomorpholinen hydrieren; in einigen Fällen gelingt diese Hydrierung auch mit H₂S, wobei jedoch die stereoisomeren Thiomorpholine gebildet werden. Thiazolo [2,3-c]-1,4-thiazine ergeben bei der Behandlung mit Ameisensäure oder NaBH₄ stereoisomere Perhydro-thiazolo[2,3-c]-1,4-thiazine.Teil der DissertationH. Diem, T. H. Aachen, 1962.