Bulk and molecular compressibilities of organic-inorganic hybrids [(CH₃)₄N]₂MnX₄ (X = Cl, Br); role of intermolecular interactions.

This work reports an X-ray diffraction, X-ray absorption, and Raman spectroscopy study of [(CH₃)₄N]₂MnX₄ (X = Cl, Br) under pressure. We show that both compounds share a similar phase diagram with pressure. A P2₁/c monoclinic structure describes precisely the [(CH₃)₄N]₂MnCl₄ crystal in the 0.

The formation of carbamate ions in interstellar ice analogues.

Carbon dioxide and ammonia are two of the most abundant species in astrophysical media, where they can react in the solid phase under certain conditions. This contribution presents a study of this reaction both in the presence of water and for anhydrous samples. It is shown that after deposition at 15 K, the reaction can start by warming the deposit, and the process continues on up to a temperature of 220 K.

Crystallization of CO2 ice and the absence of amorphous CO2 ice in space.

Carbon dioxide (CO2) is one of the most relevant and abundant species in astrophysical and atmospheric media. In particular, CO2 ice is present in several solar system bodies, as well as in interstellar and circumstellar ice mantles. The amount of CO2 in ice mantles and the presence of pure CO2 ice are significant indicators of the temperature history of dust in protostars.

Thermo- and cathodoluminescence properties of lepidolite.

Lepidolite, K(Li,Al)3(Si,Al)4O10(F,OH)2, and many of the related phyllosilicate mineral of the mica group have been well studied from the chemical and structural point of view; however, to the best of our knowledge, studies on their luminescence properties have been scarcely reported. This work focuses on the thermoluminescence (TL) and cathodoluminescence (CL) response of a natural lepidolite from Portugal previously characterized by means of environmental scanning electron microscope (ESEM) and X-ray fluorescence (XRF) and atomic absorption spectroscopy (AAS) techniques. The complexity of the thermoluminescence glow curves of non-irradiated and 1 Gy irradiated samples suggests a structure of a continuous trap distribution involving multiorder kinetics.

The structure and spectroscopy of cyanate and bicarbonate ions. Astrophysical implications.

Cyanate and bicarbonate are two ions that play active roles in many fields of physics and chemistry, including biological sciences and astrochemistry. We present here a comprehensive study of these species covering a range of phases and methodologies. We have performed theoretical calculations on the isolated ions and their hydrates with one to four water molecules, and in clusters with 15 water molecules.

Morphology and crystallization kinetics of compact (HGW) and porous (ASW) amorphous water ice.

An investigation of porosity and isothermal crystallization kinetics of amorphous ice produced either by background water vapour deposition (ASW) or by hyperquenching of liquid droplets (HGW) is presented. These two types of ice are relevant for astronomical ice research (Gálvez et al., Astrophys.

An infrared study of solid glycine in environments of astrophysical relevance.

The conversion from neutral to zwitterionic glycine is studied using infrared spectroscopy from the point of view of the interactions of this molecule with polar (water) and non-polar (CO(2), CH(4)) surroundings. Such environments could be found on astronomical or astrophysical matter. The samples are prepared by vapour-deposition on a cold substrate (25 K), and then heated up to sublimation temperatures of the co-deposited species.