No abstract available

[en] The analysis of isotopic mixtures of but-1-ene is usually performed in microwave spectroscopy by observing rotational transitions of the skew conformers. Microwave studies of the cis conformers of 1,1-d₂-, 1-¹³C- and d₈-but-1-ene allow to determine the geometry of this conformation with a very good accuracy. It follows that transition frequencies of a given isotopic species can be predicted within less than 3 MHz and be used for the isotopic chemical analysis of butene

No abstract available

No abstract available

[en] Studies of the spectroscopy of vibrationally metastable molecules are briefly described. The research concentrates on two types of molecules, complexes involving ethylene and rare gas atoms bonded to halogen molecules

[en] A technique was suggested to transform ab initio molecular force fields calculated using a set of independent vibrational coordinates into a form corresponding to a complete set of regundand coordinates and reflecting the molecular symmetry. Conditions necessary for the appropriate transformations to be possible are formulated. The possibility of transforming the force field for the simplest fragment containing regundand coordinates was demonstrated using ethylene as an example. (authors)

[en] We report details of manufacturing techniques for producing long-lived carbon foils (thickness range 4 - 24 μg/cm²) by deposition from dc ethylene discharge. We report observations on the behavior of these foils when they are used for spectral and mean-life measurements by the beam-foil method in beams of heavy ions (Br, Xe) in the 2-5 MeV energy range. We also report results of tests to determine foil life as a function of thickness as well as observations on foil shrinkage and scattering of the ion beam. (orig.)

[en] Highlights: • The reactions of H atom with propylene and isobutylene were studied using DFT methods. • The rate coefficients were calculated using CTST coupled with HO, HR and FR models. • Thermodynamic parameters are computed for all the possible channels. • Rate coefficients are useful in modeling the combustion of higher hydrocarbons. - Abstract: The rate coefficients for the reactions of hydrogen (H) atom with propylene and isobutylene were studied at M06-2X/6-31+G(d,p) and MPWB1K/6-31+G(d,p) level of theories between 200 and 2500 K. The possible mechanism for the reactions of propylene and isobutylene with H atom were examined. The rate coefficients for each reaction channels were calculated over a wide range of temperature using Conventional Transition State Theory (CTST). The quantum mechanical tunneling effect was computed using parabolic model and were included in the rate coefficient calculations. The Arrhenius expressions for the reactions, propylene + H and isobutylene + H were estimated to be k_propylene+H = (9.68 ± 0.17) × 10⁻¹⁸ T^2.16exp[−(131 ± 10)/T] cm³ molecule⁻¹ s⁻¹ and k_{isobutylene+H} = (1.40 ± 0.22) × 10⁻¹⁶ T^1.89exp[−(215 ± 12)/T] cm³ molecule⁻¹ s⁻¹, respectively. Theoretically calculated rate coefficients are found to be in good agreement with the available experimentally measured rate coefficients.

[en] The reduction of Cd(II) in propylenediamine was found to be reversible and diffusion controlled. The complexes of Cd(II) with propylenediamine in 25%, 50%, and 75% dimethylformamide have been studied polarographically using the DeFord and Hume's treatment as extended by Irving. Increase in the stability constants was observed with increase in dimethylformamide percentage. The percentage composition of the various complexed and uncomplexed species in 25% and 50% dimethylformamide are presented. (author)

[en] Challenges in the field of solid organic insulators are linked to the development of more compact, reliable and eco-friendly systems where these materials are employed as dielectrics. One way to increase the reliability of such systems is to understand and model the behavior of these materials under thermo-electrical stress, in order to prevent any failure. Fluid charge transport models have been developed to predict the charge accumulation in such materials when submitted to an external stress, mostly electrical. However, these kind of models are not enough to predict the global behavior of the material, as most of these dielectrics are polar materials, subjected to a non-negligible dipolar response. This paper shows the first simulation results produced using a global charge transport model including polarization, and compares simulated to experimental current measurements. For moderate fields and temperatures, the model is able to reproduce the experimental results, qualitatively and quantitatively. (paper)