Collision spectroscopy with aligned and oriented atoms

Neutralisation processes in 0.15–1.5 keV collisions of H^? with Na atoms in the 3s ground state or in the excited 3p state have been investigated by means of time-of-flight analysis of the neutral H atoms produced. The H^? - Na(3p) system, investigated here for the first time, is particularly interesting since the entrance channel is embedded in the [H - Na(3s)] +e ^? continuum, enabling Penning detachment to occur. The measured relative neutralisation cross section ratios σ(3p)/σ(3s) decrease from 3 to 1.6 with increasing energy. Based on earlier published results for σ(3s), σ(3p) total cross sections exceeding 100 Ų are estimated.     

Photoemission from tin and lead cluster anions

Photoelectrons from mass-identified jet-cooled tin and lead cluster anions (Sn _n ^? , Pb _n ^? ) are detached by ultraviolet laser light (hν=3.68 eV). The photoelectron energy spectra give the detachment energies of ground state cluster anions (electron affinities) as well as excitation energies of neutral clusters in the geometry of the anions. The energy spectra for Sn _n ^? are dominated by flat thresholds with ann-dependence similar to that of other group IV clusters. In contrast, for Pb _n ^? we find pronounced narrow lines close to threshold, generally followed by a 0.3–1.4 eV gap which indicates closed-shell behaviour of Pb _n ^? for nearly alln.     

Observation of in-plane carbonyl scrambling in a derivative of dodecacarbonyltriosmium.

¹³C NMR spectra obtained for the norbornadiene complex Os₃(CO)₁₀(C₇H₈)indicate restricted equilibration of in-plane carbonyls via a triply bridged intermediate. Spectral assignments are facilitated by observation of significant ¹³C-¹³C coupling between nonequivalent trans carbonyls.     

Die Kristall- und Molekülstruktur von CuBr · (C2H5)4P2 (monokline Form)

Crystal and Molecular Structure of CuBr · (C₂H₅)₄P₂ (Monoclinic Form) The crystal structure of the copper(I) complex CuBr · (C₂H₅)₄P₂ has been determined by X-ray structure analysis. The substance crystallizes monoclinic, space group C–P2₁/n with a = 10.78, b = 15.74, c = 7.54 Å, β = 84.6° and 4 formula units in the unit cell. The structure was solved by conventional heavy atom methods and has been refined to a final R-value of 0.14. The structure is characterized by continous chains, the copper atoms are tetrahedrally coordinated and linked together by alternating double bridges of two bromine atoms and two biphosphine molecues, respectively.     

Preparation of PEGMA-functionalized latex particles. 2. System styrene/<Emphasis Type="Italic">N</Emphasis>-vinylcaprolactam

In a previous paper [Pich A, Lu Y, Adler H-J (2003) Colloid Polym Sci (submitted)], the synthesis of polystyrene-poly(ethylene glycol) methacrylate (PST/PEGMA) particles has been described. In the present paper polymeric particles have been prepared by emulsion co-polymerization of styrene/N-vinylcaprolactam (ST/VCL) or styrene/n-butylacrylate (ST/BA) mixtures in presence of poly(ethylene glycol) methacrylate (PEGMA). The influence of the monomer composition and PEGMA concentration on the particle size and particle size distribution was studied. Increase of VCL content in reaction mixture leads to dramatic increase of the final particle size. Particle size distribution becomes broader at higher VCL contents. Poly(ST/VCL) particles show dramatic change of the size with the temperature.