Themed collection Theory, experiment, and simulations in laboratory astrochemistry

This Special Issue of PCCP acknowledges the synergies between laboratory and observational molecular astrophysics. It forms a collection of experimental as well as theoretical physical-chemistry investigations with the understanding of astrochemical processes as common background.

The p-H₂ matrix-isolation technique coupled with photolysis in situ or electron bombardment produces protonated or hydrogenated species important in astrochemistry.

The pure rotational spectrum of the AlC₂ radical (²A₁) has been measured using Fourier transform microwave/millimeter-wave (FTMmmW) techniques in the frequency range 21–65 GHz.

Using an off-lattice kinetic Monte Carlo model we reproduce experimental laboratory trends in the density of amorphous solid water (ASW) for varied deposition angle, rate and surface temperature. Extrapolation of the model to conditions appropriate to protoplanetary disks and interstellar dark clouds indicate that these ices may be less porous than laboratory ices.

Molecules in space are synthesized via a large variety of gas-phase reactions, and reactions on dust-grain surfaces, where the surface acts as a catalyst.

Investigation of an astrobiologically relevant prebiotic molecule, hydantoin, by broadband rotational spectroscopy and its plethora of water complexes.

Adamantane, the smallest nanodiamond molecule, dissociates mostly through C₄H₈ and C₃H₇ loss, yielding small hydrocarbons as product.

Microwave spectroscopy in a Laval flow yields isomer-specific branching.

A laboratory investigation of acetone, an interstellar and cometary molecule, has produced new results concerning its decomposition in a radiation environment.

The ro-vibrational parameters of small polyynes are calculated at the CCSD(T)/ANO1 level, including the first anharmonic vibrational frequencies of tetraacetylene.

The first emission spectrum of methyl cyanide obtained with a novel laboratory heterodyne emission spectrometer at submillimeter wavelengths.

Methoxymethanol, CH₃OCH₂OH is a very interesting candidate for detection in the interstellar medium since it can be formed in the recombination reaction between two radicals considered as intermediates in methanol formation: CH₃O (already detected in the ISM) and CH₂OH.

We present the first scattering calculations for the H₂O–CO system based on a high accuracy potential energy surface.

Combined experimental/theoretical studies demonstrate that the reaction between cyano radicals and methylamine is an efficient formation route of interstellar cyanamide.

The associative detachment reaction between H and CN⁻ at low temperature becomes possible only along a selected range of approaching directions, thus showing that there is a preferential possibility at low temperatures of forming HCN in comparison with forming CNH.

A general theoretical framework is presented that allows for the addition of cosmic ray-driven radiation chemistry to astrochemical models.

Our experimental and theoretical study investigated possible reaction mechanisms producing large anions observed by the Cassini spacecraft in Titan's atmosphere.

Temperature-programmed desorption (TPD) and reflection–absorption infrared spectroscopy (RAIRS) are used to probe the effect of atomic and molecular oxygen (O and O₂) beams on amorphous silica (aSiO₂) and water (H₂O) surfaces (porous-amorphous solid water; p-ASW, compact amorphous solid water; c-ASW, and crystalline solid water; CSW).

First collisional data for the fine-structure relaxation of interstellar S and Si by collisions with He.

PI-ReTOF-MS product analysis of methane ice processed with ionizing radiation shows that complex molecules never detected before are easily produced.

The inelastic scattering of PO (X, v = 0) has been investigated by quantum scattering calculations using a new potential energy surface.

A method is proposed to represent the potential energy surface of reactions involving polyatomic molecules, describing accurately long range interactions and saddle points, to describe low temperature collisions.