Analysis of the sequential photodissociation dynamics of sulfur dichloride, phosphorus trichloride, thiophosphoryl chloride, and bromomethane applying a 3D imaging technique

Das Ziel der Forschung ist das fundamentale Verständnis chemischer Reaktionen. Die Untersuchung des Mechanismus von Fragmentationsprozessen führt zu detaillierten Kenntnissen auf dem Gebiet komplexer Reaktionsprozesse wie Prozesse in der Atmosphärenchemie und Verbrennungsprozesse. Wir wollen mit vollständiger Auflösung der Quantenzustände wissen, auf welchem Weg sich das System auf der angeregten Hyperpotentialfläche bewegt. Um diese Fragen zu beantworten, wurde die sequentielle Photodissoziationsdynamik von Schwefeldichlorid, Phosphortrichlorid, Thiophosphorylchlorid und Brommethan mittels 3D-Imaging des Photodissoziationsproduktes Chlor bzw. Brom im Grundzustand und spin-bahn-angeregten Zustand untersucht. Das dreidimensionale Photofragment-Imaging beinhaltet einen kalten Überschallmolekularstrahl, einen zustandselektiven REMPI-Nachweis der Photofragmente und ein Flugzeitmassenspektrometer in Kombination mit einem positionssensitiven Detektor für die Ionen. Mit diesem Verfahren wird der vollständige dreidimensionale Geschwindigkeitsvektor eines Reaktionsproduktes direkt bestimmt.The aim of the research is the fundamental understanding of chemical reactions. The study of the mechanism of fragmentation processes provides detailed knowledge in the field of complex reaction processes, as there are processes in atmospheric chemistry and combustion processes. We want to know which way the system will follow on the excited potential energy surface in the full quantum state definition. To answer these questions the sequential photodissociation dynamics of sulfur dichloride, phosphorus trichloride, thiophosphoryl chloride, and bromomethane have been studied by 3D imaging of the photodissociation product chlorine or bromine respectively in the ground state and the excited spin-orbit state. The three-dimensional photofragment imaging technique includes a cold supersonic molecular beam, a state-selective REMPI detection of the photofragments, and a TOF mass spectrometer combined with a position-sensitive detector for ions. Applying this technique the complete three-dimensional velocity vector of a reaction product is directly determined

Pericenter passage of the gas cloud G2 in the Galactic Center

We have further followed the evolution of the orbital and physical properties of G2, the object currently falling toward the massive black hole in the Galactic Center on a near-radial orbit. New, very sensitive data were taken in April 2013 with NACO and SINFONI at the ESO VLT . The 'head' of G2 continues to be stretched ever further along the orbit in position-velocity space. A fraction of its emission appears to be already emerging on the blue-shifted side of the orbit, past pericenter approach. Ionized gas in the head is now stretched over more than 15,000 Schwarzschild radii RS around the pericenter of the orbit, at ~ 2000 RS ~ 20 light hours from the black hole. The pericenter passage of G2 will be a process stretching over a period of at least one year. The Brackett-{\gamma} luminosity of the head has been constant over the past 9 years, to within +- 25%, as have the line ratios Brackett-{\gamma} / Paschen-{\alpha} and Brackett-{\gamma} / Helium-I. We do not see any significant evidence for deviations of G2's dynamical evolution, due to hydrodynamical interactions with the hot gas around the black hole, from a ballistic orbit of an initially compact cloud with moderate velocity dispersion. The constant luminosity and the increasingly stretched appearance of the head of G2 in the position-velocity plane, without a central peak, is not consistent with several proposed models with continuous gas release from an initially bound zone around a faint star on the same orbit as G2.Comment: 10 figures, submitted to Ap

The Confederate And Independent Signal Corps

The Confederate Signal Corps and the Independent Signal Corps are two organizations in the Civil War which are cloaked in general ignorance. In fact, several leading historians on the Civil War confessed their lack of knowledge, or even general knowledge, about the Confederate Signal Corps (the Independent Signal Corps was not mentioned since its existence is generally unknown). For these reasons, the problem of trying to gather the available information on the Confederate Signal Corps and Independent Signal Corps in order to comprehend them in their true perspective was undertaken