相关论文: Molecular dynamics simulations of the ice temperat…
We present results of classical dynamics calculations, performed to study the photodissociation of water in crystalline and amorphous ice surfaces at a surface temperature of 10 K. Dissociation in the top six monolayers is considered.…
Molecular dynamics calculations have been performed to study the ultraviolet photodissociation of D2O in an amorphous D2O ice surface at 10-90 K, in order to investigate the influence of isotope effects on the photodesorption processes. As…
Absorption of ultraviolet radiation by water ice coating interstellar grains can lead to dissociation and desorption of the ice molecules. These processes are thought to be important in the gas-grain chemistry in molecular clouds and…
Ultraviolet irradiation of ice is of great interest for understanding the chemistry in both atmospheric and astrophysical environments. In interstellar space, photodissociation of H2O molecules can be a driving force behind the chemistry on…
Gaseous H2O has been detected in several cold astrophysical environments, where the observed abundances cannot be explained by thermal desorption of H2O ice or by H2O gas phase formation. These observations hence suggest an efficient…
The HDO/H2O ratio in interstellar gas is often used to draw conclusions on the origin of water in star-forming regions and on Earth. In cold cores and in the outer regions of protoplanetary disks, gas-phase water comes from photodesorption…
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…
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 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…
Aims. The mobility of H atoms on the surface of interstellar dust grains at low temperature is still a matter of debate. In dense clouds, the hydrogenation of adsorbed species (i.e., CO), as well as the subsequent deuteration of the…
We investigated the behavior of H$_2$, main constituent of the gas phase in dense clouds, after collision with amorphous solid water (ASW) surfaces, one of the most abundant chemical species of interstellar ices. We developed a general…
A longstanding problem in astrochemistry is how molecules can be maintained in the gas phase in dense inter- and circumstellar regions. Photodesorption is a non-thermal desorption mechanism, which may explain the small amounts of observed…
Electronic excitations near the surface of water ice lead to the desorption of adsorbed molecules, through a so far debated mechanism. A systematic study of photon-induced indirect desorption, revealed by the spectral dependence of the…
At the high densities and low temperatures found in star forming regions, all molecules other than H2 should stick on dust grains on timescales shorter than the cloud lifetimes. Yet these clouds are detected in the millimeter lines of…
CO$_2$ ice has a phase transition at 35 K when its structure changes from amorphous to crystalline. Using Reflection absorption Infrared Spectroscopy (RAIRS), \"Oberg et al. observed that the photodesorption yield of CO$_2$ ice deposited at…
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…
UV-induced photodesorption of ice is a non-thermal evaporation process that can explain the presence of cold molecular gas in a range of interstellar regions. Information on the average UV photodesorption yield of astrophysically important…
The photodesorption efficiencies of the hydroxyl (OH) radical from the water ice surface were measured in the range of 310-700 nm for the first time. Although isolated H$_2$O molecules and OH radicals do not absorb visible photons, the…
Using a combination of photostimulated desorption and resonance-enhanced multiphoton ionization methods, the behaviors of OH radicals on the surface of interstellar ice analog was monitored at temperatures between 54 and 80 K. The OH number…
Ice desorption affects the evolution of the gas-phase chemistry during the protostellar stage, and also determines the chemical composition of comets forming in circumstellar disks. From observations, most volatile species are found in…