Diversity of chemistry and excitation conditions in the high-mass star forming complex W33

The object W33 is a giant molecular cloud that contains star forming regions at various evolutionary stages from quiescent clumps to developed H II regions. Since its star forming regions are located at the same distance and the primary material of the birth clouds is probably similar, we conducted a comparative chemical study to trace the chemical footprint of the different phases of evolution. We observed six clumps in W33 with the Atacama Pathfinder Experiment (APEX) telescope at 280 GHz and the Submillimeter Array (SMA) at 230 GHz. We detected 27 transitions of 10 different molecules in the APEX data and 52 transitions of 16 different molecules in the SMA data. The chemistry on scales larger than $\sim$0.2 pc, which are traced by the APEX data, becomes more complex and diverse the more evolved the star forming region is. On smaller scales traced by the SMA data, the chemical complexity and diversity increase up to the hot core stage. In the H II region phase, the SMA spectra resemble the spectra of the protostellar phase. Either these more complex molecules are destroyed or their emission is not compact enough to be detected with the SMA. Synthetic spectra modelling of the H$_{2}$CO transitions, as detected with the APEX telescope, shows that both a warm and a cold component are needed to obtain a good fit to the emission for all sources except for W33 Main1. The temperatures and column densities of the two components increase during the evolution of the star forming regions. The integrated intensity ratios N$_{2}$H$^{+}$(3$-$2)/CS(6$-$5) and N$_{2}$H$^{+}$(3$-$2)/H$_{2}$CO(4$_{2,2}$$-$3$_{2,1}$) show clear trends as a function of evolutionary stage, luminosity, luminosity-to-mass ratio, and H$_{2}$ peak column density of the clumps and might be usable as chemical clocks.Comment: 66 pages, 28 figures, 8 tables, accepted for publication at A&

Neue Duennschichtverfahren durch Molecular Engineering Metallorganischer Verbindungen. Teilvorhaben: MOV-Synthese Abschlussbericht

1) Using metal- and element chlorides in addition with ammonia as reacting gas to create thin films of metal- and element nitrides (TiN, BN, AlN). Using aluminium trialkyls and trimethylamin-alan to generate thin films of aluminium. Tungstenhexafluoride as precursor for tungsten-CVD. 2) Presenting new perspectives in generating of thin films of metals, metal- and element nitrides by working out and evaluation of new suitable OMCVD-precursors. 3) Working out and synthesis of small amounts of volatile, decomposable compounds with compositions and structures accomodated to the required properties of the layer by molecular engineering. Analyses of these compounds with regard to structure, physical datas and properties. Preliminary CVD-investigations; analysis of the layers by scanning microscopy, X-ray and measurement of conductivity. 4) Synthesis, characterisation and CVD-investigations of these special organometallic compounds with regard to point 3. 5) Suitable OMCVD-precursors for depositing thin films of copper, boron nitride, titanium and titanium nitride could be found, evaluated and -especially in the case of copper (tert-Butylisonitrile-complexes)- successfully prooved to be fit for CVD-process. (orig.)SIGLEAvailable from TIB Hannover: F95B913+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman