Emission spectra and gas products of microwave discharge in liquid n‐heptane with and without argon bubbling (6–40 l h−1) are investigated. The discharge was excited in a system with a coaxial input of energy. The pressure above the surface of the liquid was equal to atmospheric pressure. It is shown that the addition of argon changes the spectral composition of the plasma radiation, in which the emission of hydrogen and argon atomic lines appears. The addition of argon does not affect the rotational and vibrational temperatures of the state C2true(d3normalΠgtrue), the composition and the ratio of the main gas products (H2, CH4, C2H2, C2H4).

Carbon‐containing nanosize solid‐state phase have been produced in the atmospheric pressure microwave (MW) plasma ignited in the gas bubbles in liquid alkanes CnH2n+2 (n = 7, 8, 10, 15, 16). Gas bubbles are generated by flow of argon. According to SEM data, the solid‐state products are represented by particles having dimensions in the range of 100–200 nm. Raman spectra of the sooty‐like unpurified solid products permit to categorize them as sp3+sp2 mixed forms of carbon comprising mainly an “damaged grapheme” along with a “few‐layer” graphite nanoparticles. NMR spectra of the solid products show strong aromatization and formation of various unsaturated molecular fragments. FTIR‐ATR spectra indicate that the carbonaceous nanoparticles are contaminated with minor amounts of different hydrocarbon residues and oxidized species.

We present the analysis of the impedance spectra for a binary electrolyte confined between blocking electrodes with dielectric layers. An expression for the impedance is derived from Poisson-Nernst-Planck equations in the linear approximation taking into account the voltage drop on the dielectric layer. The analysis shows, that characteristic features of the frequency dependence of the impedance are determined by the ratio of the Debay length and the effective thickness of the dielectric layer. The impact of the dielectric layer is especially strong in the case of high concentrated electrolytes, where the Debay length is small and thus comparable to the effective thickness of the dielectric layer. To verify the model, measurements of the impedance spectra and transient currents in a liquid crystal 4-n-pentyl-4'-cyanobiphenyl (5CB) confined between polymercoated electrodes in cells of different thicknesses are performed. The estimates for the diffusion coefficient and ion concentration in 5CB obtained from the analysis of the impedance spectra and the transient currents are consistent and agree with previously reported data. We demonstrate that calculations of the ion parameters from the impedance spectra without taking into account the dielectric layer contribution lead in most cases to incorrect results. Application of the model to analyze violations of the low-frequency impedance scaling and contradictions in the estimates of the ion parameters recently found in some ionic electrolytes are discussed. * maxim@anrb.ru arXiv:1804.04843v1 [cond-mat.soft]