Related papers: Indirect ultraviolet photodesorption from CO:N2 bi…
The detection of high gas-phase abundances of SO2 and SO in the cold envelope of an intermediate mass protostar suggests that these molecules might form on icy dust grains and subsequently desorb to the gas phase by non-thermal desorption…
The overabundance of gas molecules in the coldest regions of space point to a non-thermal desorption process. Laboratory simulations show an efficient desorption of CO ice exposed to ultraviolet radiation, known as photodesorption, which…
We present Temperature Programmed Desorption (TPD) experiments of CO and N2 ices in pure, layered and mixed morphologies at various ice "thicknesses" and abundance ratios as well as simultaneously taken Reflection Absorption Infrared…
We study the photo-desorption occurring in H$_2$O:CO:NH$_3$ ice mixtures irradiated with monochromatic (550 and 900 eV) and broad band (250--1250 eV) soft X-rays generated at the National Synchrotron Radiation Research Center (Hsinchu,…
Solid-phase photo-processes involving icy dust grains greatly affect the chemical evolution of the interstellar medium by leading to the formation of complex organic molecules and by inducing photodesorption. So far, the focus of laboratory…
Water (H2O) ice is an important solid constituent of many astrophysical environments. To comprehend the role of such ices in the chemistry and evolution of dense molecular clouds and comets, it is necessary to understand the freeze-out,…
The desorption of molecular species from ice mantles back into the gas phase in molecular clouds results from a variety of very poorly understood processes. We have investigated three mechanisms; desorption resulting from H_2 formation on…
Molecular oxygen, nitrogen, and ozone have been detected in the Solar System. They are also expected to be present in ice-grain mantles within star-forming regions. Laboratory experiments that simulate energetic processing (ions, photons,…
Vacuum-UV (VUV) photodesorption from water-rich ice mantles coating interstellar grains is known to play an important role in the gas-to-ice ratio in star- and planet-forming regions. Quantitative photodesorption yields from water ice are…
The relative desorption energies of CO and N$_2$ are key to interpretations of observed interstellar CO and N$_2$ abundance patterns, including the well-documented CO and N$_2$H$^+$ anti-correlations in disks, protostars and molecular cloud…
Diffusion of species in icy dust grain mantles is a fundamental process that shapes the chemistry of interstellar regions; yet measurements of diffusion in interstellar ice analogs are scarce. Here we present measurements of CO diffusion…
Non-thermal desorption of inter- and circum-stellar ice mantles on dust grains, in particular ultraviolet photon-induced desorption, has gained importance in recent years. These processes may account for the observed gas phase abundances of…
Solid O2 has been proposed as a possible reservoir for oxygen in dense clouds through freeze-out processes. The aim of this work is to characterize quantitatively the physical processes that are involved in the desorption kinetics of CO-O2…
The occurrence of complex organic molecules (COMs) in the gas phase at low temperature in the dense phases of the ISM suggests that a non-thermal desorption mechanism is at work because otherwise, COMs should condense within a short…
Methanol and formaldehyde are two simple organic molecules that are ubiquitously detected in the interstellar medium. An origin in the solid phase and a subsequent nonthermal desorption into the gas phase is often invoked to explain their…
Currently ~36 different absorption bands have been detected in the infrared spectra of cold, dense interstellar and circumstellar environments. These are attributed to the vibrational transitions of ~17 different molecules frozen on dust…
The photodesorption of icy grain mantles has been claimed to be responsible for the abundance of gas-phase molecules toward cold regions. Being water a ubiquitous molecule, it is crucial to understand its role in photochemistry and its…
In regions where stars form, variations in density and temperature can cause gas to freeze-out onto dust grains forming ice mantles, which influences the chemical composition of a cloud. The aim of this paper is to understand in detail the…
Carbonic acid (H2CO3) is a weak acid relevant to astrobiology which, to date, remains undetected in space. Experimental work has shown that the beta-polymorph of H2CO3 forms under space relevant conditions through energetic (UV photon,…
Context. In dense clouds, hydrogenation reactions on icy dust grains are key in the formation of molecules, like formaldehyde, methanol, and complex organic molecules (COMs). These species form through the sequential hydrogenation of CO…