The line intensities and pressure broadening coefficients for transitions in the three branches of the ν2 parallel band of CH3I are measured for the first time for about 1317 lines with rotational quantum numbers 2 ≤ J ≤ 70 and 0 ≤ K ≤ 13 using a mono-spectrum fitting technique utilizing a Voigt profile. Five spectra have been recorded at room temperature (T = 297.6 K) with a high resolution Fourier transform spectrometer at pressures between 1.15 and 9.98 mbar. The measured intensities were used to derive the transition dipole moment squared for each line, the band intensity as well as the Herman–Wallis coefficients. These parameters were used to predict the values of line intensities. The band intensity was compared with previous works performed at medium resolution. The rotational dependencies of the self-broadening coefficients have been clearly observed and modeled using an empirical model. The average accuracies were estimated to be around 5 % for line intensities and self-broadening coefficients.

Methanol, which is one of the most abundant organic molecules in the interstellar medium, plays an important role in the complex grain surface chemistry that is believed to be a source of many organic compounds. Under energetic processing such as ultraviolet (UV) photons or cosmic rays, methanol may decompose into CH4, CO2, CO, HCO, H2CO, CH3O and CH2OH, which in turn lead to complex organic molecules such as CH3OCHO, CHOCH2OH and HOCH2CH2OH through radical recombination reactions. However, although molecular oxygen and its detection, abundance and role in the interstellar medium have been the subject of many debates, few experiments on the oxidation of organic compounds have been carried out under interstellar conditions. The present study shows the behaviour of solid methanol when treated by UV light and thermal processing in oxygen-rich environments.

Astronomical observations have already reported that the abundances of NH, NH2, and NH3 cannot be explained with gas phase chemistry modeling and depend strongly on the environment where these three N-hydrides have been detected. Consequently, dust grains may play a crucial role in the formation of these species through surface reactions. We have investigated the formation of NH, NH2 and NH3 through N ->(+H) NH ->(+H) NH2 ->(+H) NH3 solid state reaction at 3 and 10 K, in different environments. The N-2-H-2 gas binary mixture is then plasma activated and the resulting gas from the microwave discharge made of H, H-2, N, N-2 and NH3 is deposited onto the surface of the sample holder maintained at 3 and 10 K. We show that, while at 10 K, NH, NH2 and NH3 have been detected in different abundance distributions, at 3 K the NH and NH2 radicals have not observed and the low amount of NH3 present in our solid samples comes from the N-2-H-2 plasma discharge. This is the first experimental study showing all the steps leading to ammonia formation, by detecting the final reaction product NH3 and the two reaction intermediates NH and NH2.

Proton chemistry is a fascinating field with both fundamental and applied aspects. The development of solid-state proton conductors relying on abundant elements could help bring these two aspects. In this scope, we synthesized a disordered structure which, as revealed by the real-space refinement of the pair distribution function, has been identified to be the trititanate arrangement. The layered structure is stabilized by the presence of hydronium ions and water molecules located in the interlayer space. This compound displays a high ionic conductivity of 4·10–2 S/m with an activation energy of 0.24 eV, assigned to H+ mobility as shown by broadband dielectric spectroscopy. Proton mobility was further evidenced by solid-state proton nuclear magnetic resonance. Density functional theory calculations revealed that proton transfer occurs both within the interlayer space and with terminal oxide of the titanate framework through a Grotthuss-based mechanism rationalizing the high conductivity measured experimentally...

Following a previous work on recommended 12C2H2 line list for the 13 − 248 cm–1 and 390 − 634 cm–1 spectral regions, the present work is dedicated on new measurements between 638 and 820 cm–1. Line intensities have been measured for 18 bands: only four of them were previously reported. The measurements allowed validating predictions based on the global modeling of the line positions and intensities performed within the framework of the method of effective operators. Using the present new measurements as well as previous measurements from literature, new fittings of the line intensities for the ∆P = 1 series of transitions have been performed. A complete calculated line list of 200 bands belonging of the ∆P = 1 series of transitions is proposed as supplementary data in order to improve such spectroscopic databases as HITRAN or GEISA.