相关论文: Water transport through mesoporous amorphous-carbo…
Context. The diffusion of volatile species on amorphous solid water ice affects the chemistry on dust grains in the interstellar medium as well as the trapping of gases enriching planetary atmospheres or present in cometary material. Aims.…
When water molecules are confined to nanoscale spacings, such as in the nanometer size pores of activated carbon fiber (ACF), their freezing point gets suppressed down to very low temperatures ($\sim$ 150 K), leading to a metastable liquid…
The diffusion of molecules on interstellar grain surfaces is one of the most important driving forces for the molecular complexity in the interstellar medium. Due to the lack of laboratory measurements, astrochemical modeling of grain…
The diffusion of atoms and molecules in ices covering dust grains in dense clouds in interstellar space is an important but poorly characterized step in the formation of complex molecules in space. Here we report the measurement of…
The diffusion of atoms and radicals on interstellar dust grains is a fundamental ingredient for predicting accurate molecular abundances in astronomical environments. Quantitative values of diffusivity and diffusion barriers usually rely…
We investigate water and deuterated water chemistry in turbulent protoplanetary disks. Chemical rate equations are solved with the diffusion term, mimicking turbulent mixing in vertical direction. Water near the midplane is transported to…
Adsorption of water vapor in nanoporous carbons is rather complex due to an interplay between the pore structure and surface chemistry of these materials. Deciphering the mechanism of adsorption requires the knowledge of the spatial…
The long-timescale behavior of adsorbed carbon monoxide on the surface of amorphous water ice is studied under dense cloud conditions by means of off-lattice, on-the-fly, kinetic Monte Carlo simula- tions. It is found that the CO mobility…
We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes, with different degrees of eccentricity at 300K. We found a water structural transition between tubular-like to single-file for the (7,7)…
Surface chemistry on interstellar dust grains is recognized as a central component in astrochemical models, representing a plausible formation route for many of the observed complex molecular species. However, key parameters governing…
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 D/H ratios of carbonaceous chondrites, believed to reflect that of water in the inner early solar system, are intermediate between the protosolar value and that of most comets. The isotopic composition of cometary water has been…
Water vapor has been detected in protoplanetary disks. In this work we model the distribution of water vapor in protoplanetary disks with a thermo-chemical code. For a set of parameterized disk models, we calculate the distribution of dust…
Diffusion of atoms and molecules is a key process for the chemical evolution in the star forming regions of the interstellar medium. Accurate data on the mobility of many important interstellar species is however often not available and…
We use molecular dynamics simulations to study the diffusion of water inside deformed carbon nanotubes with different degrees of deformation at 300 K. We found that the number of hydrogen bonds that water forms depends on nanotube topology,…
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…
It is shown that structuring at the microlevel, a previously not described in detail phenomenon, is the intrinsic property of water and aqueous solutions. At room conditions water (including "ultrapure" one) and aqueous solutions are…
Context. The level of porosity of interstellar ices - largely comprised of amorphous solid water (ASW) - contains clues on the trapping capacity of other volatile species and determines the surface accessibility that is needed for solid…
Observations by ISO and Spitzer towards young stellar objects (YSOs) showed that CO$_2$ segregates in the icy mantles covering dust grains. Thermal processing of ice mixture was proposed as responsible for the segregation. Although several…
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…