2-Azidoacetic acid (N3CH2CO2H) has been synthesized and characterized by a variety of spectroscopic techniques, and the thermal decomposition of this molecule studied by matrix isolation infrared spectroscopy and real-time ultraviolet photoelectron spectroscopy. The results are consistent with the vapor phase thermal decomposition following a pathway involving concerted ejection of molecular N2 and the simultaneous formation of CO2 and methanimine (CH2NH). No evidence was found for the presence of intermediates such as the nitrene NCH2CO2H or the imine HNCHCO2H. At higher temperatures, CH2NH further decomposes to give HCN and H2.

The amount of counterions in layer-by-layer (LBL) films of poly(allylamine hydrochloride) (PAH) and poly(styrene sulfonate) (PSS) has been determined with X-ray photoelectron spectroscopy (XPS) for films prepared from solutions with various NaCl concentrations. Sodium and chloride counterions are present in LBL films produced from salt solutions, which are located at the surface and in the bulk of the films. The percentage of bulk counterions increases with the ionic strength of the polyelectrolyte before reaching a constant value. The bulk sodium/sulfur percentage ratios tend to 0.8 for samples washed with pure water and for samples washed with NaCl aqueous solutions, while the bulk chlorine/nitrogen percentage ratios tend to 0.5 for the same samples. The ratio between the percentages of polyelectrolyte ionic groups lies close to unity for all samples, indicating that counterions do not contribute to charge compensation in the polyelectrolyte during the adsorption process. The presence of counterions in LBL films is explained by Manning condensation near the polyelectrolyte ionic groups, leading to inter-polyelectrolyte ionic bondings via ionic networks. It is believed that condensation leads to the formation of NaCl crystallites in these LBL films, which was confirmed by X-ray diffraction measurements.

The thermal decompositions of 2-azidoethanol and 2-azidoethyl acetate have been studied by matrix isolation infrared spectroscopy and real-time ultraviolet photoelectron spectroscopy. The products that were detected in a flow system at different temperatures (CH2NH, H2CO, N2, CO, and HCN from N3CH2CH2OH and C2H4, CH2NH, HCN, CO2, and N2 from N3CH2COOCH2CH3) allowed mechanisms for decomposition to be proposed. The experimental evidence obtained is consistent with 2-azidoethyl actetate decomposing via a concerted mechanism, similar to that found previously for azidoacetic acid, whereas the 2-azidoethanol decomposition is consistent with a stepwise decomposition mechanism as observed previously for azidoacetone.

2-Azidoacetone (N3CH2COCH3) has been synthesized and characterized by a variety of spectroscopic techniques, and the thermal decomposition of this molecule at temperatures in the region 300−1150 K has been studied by matrix isolation infrared spectroscopy and real-time ultraviolet photoelectron spectroscopy. The results show the effectively simultaneous production of six prominent decomposition products:  CH2NH, CH2CO, HCN, CO, N2, and CH3CHO, and several reaction pathways are proposed to account for their formation. Results of ab initio molecular orbital calculations indicate that the primary reaction intermediate is the imine HNCHCOCH3, with the nitrene NCH2COCH3 being a transition state. No experimental evidence was found for the presence of the imine HNCHCOCH3, but mechanistic considerations, and the existence of several weak unassigned IR bands point to the presence of a further decomposition product, which may be CH2NCH3.

In this paper we report on complementary measurements on ion-pair formation in collisions between K atoms and CH 3 N0 2 molecules. The experiments were performed in a c.m. energy range from 20 up to 300 eV. Double differential cross sections were obtained by measuring the K + ion yield as a function of the scatter angle and as a function of the post-collision laboratory energy. On the other hand, relative total partial cross sections for the formation of CH 3 N0 2 -, N0 2 -, and 0 -were measured in the same energy range. The experimental results lead to the conclusion that in this energy range electron transfer takes place to three ionic states ofCH 3 NO; , a dominantly repulsive 2AI state and two 2EI states with relatively deep potential wells. 166 J. Chem. Phys. 95 (1).1

Negative ion formation in alkali-atom-molecule collisions is a powerful method to study the dynamic properties of negative ions. By studying a collision with an electron donor such as an alkali atom one has access to the electron affinity of the molecule as it is manifested in the collision. The electron affinities obtained depend on the conditions of the collision and do not have to be identical to electron affinities obtained by other means. In this way adiabatic, vertical and reactive electron affinities can be discerned. Moreover if the collision energy is in the eV region one can probe the vibrational dynamics of a negative molecular ion on a 10 fs timescale.As a theoretical introduction to negative ion formation by electron transfer in atom-molecule collisions the curve crossing model and the collision dynamics of the atom-atom case are briefly reviewed.A short survey of the experimental methods used is presented. Measurements of total, differential and double-differential cross sections as a function of the collision energy and different collision partners are discussed.In atom-molecule collisions stretching of the bond of the molecular negative ion during the collision is among the most relevant consequences of the internal degrees of freedom of the molecule. The collision dynamics explored in this way not only gives insight into the properties of negative ions, but also into the dynamics of elementary processes occurring in chemical reactions.

Thermally assisted transmethylation gas chromatography ‐ mass spectrometry with tetramethylammonium hydroxide has been applied for the qualitative and quantitative analysis of the suberin fraction of wax‐free cork. With this method, hydrolysis of esters together with methylation of carboxylic and hydroxylic groups was observed. Mostly long chain aliphatic components, such as alkanols, alkanoic acids, ω‐hydroxyacids, α,ω‐alkanoic diacids, and several 9,10‐epoxy and 9,10‐dihydroxy forms have been found in keeping with results of other workers in the field. Two other components that may give a more complete view of the architecture of suberin were also found, namely the phenolic compound ferulic acid, and glycerol which is probably esterified to carboxylic groups of the aliphatic building units of suberin. © 1998 John Wiley & Sons, Ltd.

Time-of-flight secondary ion mass spectrometry was used to study four human calculi and to compare the results with those from twelve commercially available urinary calculi minerals including three organic compounds (L-cystine, uric acid and sodium urate). Phase identification of calcium phosphate compounds was carried out by considering the relative ion abundances of [Ca(2)O](+) and [CaPO(2)](+). Deprotonated [M-H](-) and protonated [M+H](+) uric acid were detected and used for component recognition in pure uric acid and in the mixed samples of struvite, calcium oxalate and uric acid. Iodine related to the medical history of a patient was also detected.