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.
Spectroscopy of prospective interstellar ions and radicals isolated in para-hydrogen matrices
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 T-shaped AlC2 radical (X̃2A1)
The pure rotational spectrum of the AlC2 radical (X̃2A1) has been measured using Fourier transform microwave/millimeter-wave (FTMmmW) techniques in the frequency range 21–65 GHz.
Kinetic Monte Carlo simulations of water ice porosity: extrapolations of deposition parameters from the laboratory to interstellar space
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.
Molecular dynamics simulations of energy dissipation and non-thermal diffusion on amorphous solid water
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.
Where's water? The many binding sites of hydantoin
Investigation of an astrobiologically relevant prebiotic molecule, hydantoin, by broadband rotational spectroscopy and its plethora of water complexes.
Dissociative ionisation of adamantane: a combined theoretical and experimental study
Adamantane, the smallest nanodiamond molecule, dissociates mostly through C4H8 and C3H7 loss, yielding small hydrocarbons as product.
Isomer-specific detection in the UV photodissociation of the propargyl radical by chirped-pulse mm-wave spectroscopy in a pulsed quasi-uniform flow
Microwave spectroscopy in a Laval flow yields isomer-specific branching.
Radiation chemistry of solid acetone in the interstellar medium – a new dimension to an old problem
A laboratory investigation of acetone, an interstellar and cometary molecule, has produced new results concerning its decomposition in a radiation environment.
Theoretical investigation of the infrared spectrum of small polyynes
The ro-vibrational parameters of small polyynes are calculated at the CCSD(T)/ANO1 level, including the first anharmonic vibrational frequencies of tetraacetylene.
A laboratory heterodyne emission spectrometer at submillimeter wavelengths
The first emission spectrum of methyl cyanide obtained with a novel laboratory heterodyne emission spectrometer at submillimeter wavelengths.
Laboratory spectroscopy of methoxymethanol in the millimeter-wave range
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.
Interaction of H2O with CO: potential energy surface, bound states and scattering calculations
We present the first scattering calculations for the H2O–CO system based on a high accuracy potential energy surface.
Low temperature kinetics and theoretical studies of the reaction CN + CH3NH2: a potential source of cyanamide and methyl cyanamide in the interstellar medium
Combined experimental/theoretical studies demonstrate that the reaction between cyano radicals and methylamine is an efficient formation route of interstellar cyanamide.
Associative detachment (AD) paths for H and CN− in the gas-phase: astrophysical implications
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 method for the inclusion of radiation chemistry in astrochemical models
A general theoretical framework is presented that allows for the addition of cosmic ray-driven radiation chemistry to astrochemical models.
The reaction of C5N− with acetylene as a possible intermediate step to produce large anions in Titan's ionosphere
Our experimental and theoretical study investigated possible reaction mechanisms producing large anions observed by the Cassini spacecraft in Titan's atmosphere.
Impact of oxygen chemistry on model interstellar grain surfaces
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).
Fine-structure transitions of interstellar atomic sulfur and silicon induced by collisions with helium
First collisional data for the fine-structure relaxation of interstellar S and Si by collisions with He.
Untangling the methane chemistry in interstellar and solar system ices toward ionizing radiation: a combined infrared and reflectron time-of-flight analysis
PI-ReTOF-MS product analysis of methane ice processed with ionizing radiation shows that complex molecules never detected before are easily produced.
Collisional excitation of interstellar PO(X2Π) by He: new ab initio potential energy surfaces and scattering calculations
The inelastic scattering of PO (X, v = 0) has been investigated by quantum scattering calculations using a new potential energy surface.
Full dimensional potential energy surface and low temperature dynamics of the H2CO + OH → HCO + H2O reaction
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.
About this collection
Guest-edited by Laurent Wiesenfeld (Université Grenoble Alpes), Allan Shi-Chung Cheung (The University of Hong Kong) and Jos Oomens (Radboud University), this themed issue of PCCP overviews the recent developments showing physical insights in the areas of theory, experiment, and simulation as applied to molecular astrophysics environments.