Laboratory surface astrochemistry experiments

Phys. Chem. Chem. Phys.

et al. 2017

The surface heterogeneity of amorphous silica (aSiO) has been probed using coverage dependent temperature programmed desorption (TPD) of a simple probe molecule, carbon monoxide (CO). The resulting distribution of interaction energies is the foundation from which an environmentally broadened vibrational line profile synthesis has been undertaken. These simulations are compared with measured line profiles recorded at 0.1 cm resolution using reflection-absorption infrared spectroscopy (RAIRS). A comparison of such line profile synthesis for CO on amorphous silica and on porous amorphous solid water (p-ASW) is also reported and conclusions are drawn as to the vibrational relaxation and surface dynamics of the CO molecule on the two surfaces.

Section: Methodsmentioning

confidence: 99%

Surface heterogeneity and inhomogeneous broadening of vibrational line profiles

Taj

Baird

Phys. Chem. Chem. Phys.

et al. 2017

“…The experimental apparatus, ancillary equipment, and general methods employed have been described in detail previously. − Herein, only details specific to the reported measurements are given. Gas doses are reported in Langmuir units (1 L = 10 –6 Torr s).…”

Section: Methodsmentioning

confidence: 99%

Surface Science Investigations of Icy Mantle Growth on Interstellar Dust Grains in Cooling Environments

Marchione

Taj

et al. 2019

ACS Earth Space Chem.

Experimental measurements on the thermal and non-thermal behaviour of water and other simple molecules, including organic compounds such as methanol and benzene, on model interstellar dust grain surfaces and on solid water surfaces using surface science 1 Page 1 of 61 ACS Paragon Plus Environment ACS Earth and Space Chemistry techniques and methodologies are reviewed. A simple qualitative model of the early stages mantle growth arising from a synthesis of the results of such investigations from our own laboratory and others is presented.

“…RAIRS experiments were performed in an ultrahigh vacuum system, described in detail elsewhere. 17,18 The substrate, an oxygen-free high conductivity copper block coated with a 300 nm amorphous silica layer, 19 is mounted on the end of a closed-cycle helium cryostat, reaching a base temperature of 18 K, measured with a KP-type thermocouple connected to an IJ-6 temperature controller (IJ Instruments). The central chamber is equipped with a line-of-sight quadrupole mass spectrometer (QMS, Hiden Analytical) and a Fourier-transform infrared spectrometer (Varian 670-IR) used in reflection-absorption mode, at a grazing incidence of 751 with respect to the normal to the substrate.…”

Section: The Experimental Methodsmentioning

confidence: 99%

Spontaneous electric fields in solid carbon monoxide

Lasne

Phys. Chem. Chem. Phys.

Cassidy

et al. 2015

Reflection-absorption infrared spectroscopy (RAIRS) is shown to provide a means of observing the spontelectric phase of matter, the defining characteristic of which is the occurrence of a spontaneous and powerful static electric field within a film of material. The presence of such a field is demonstrated here through the study of longitudinal-transverse optical splitting in RAIR spectra in films of carbon monoxide, based upon the deposition temperature dependence of this splitting. Analysis of spectral data, in terms of the vibrational Stark effect, allows the measurement of the polarization of spontelectric films, showing for example that solid carbon monoxide at 20 K may maintain a spontelectric field of 3.78 × 10(7) V m(-1), representing a polarization of 3.34 × 10(-4) cm(-2). We comment on the astrophysical implications of polarized carbon monoxide ices, on the surface of cosmic grains in star-forming regions.