Thermal desorption of ammonia from crystalline forsterite surfaces

Suhasaria, T.; Thrower, J. D.; Zacharias, H.

doi:10.1093/mnras/stv2197

Cited by 28 publications

(34 citation statements)

References 69 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The sample was a synthetic forsterite single crystal, cleaved to expose the most stable forsterite(010), as confirmed through reflective diffraction measurements (Suhasaria et al 2015;King et al 2010). To understand the surface morphology, tapping mode atomic force microscopy (AFM) was used.…”

Section: Experimental Methodsmentioning

confidence: 94%

Thermal desorption of astrophysically relevant molecules from forsterite(010)

Suhasaria¹,

Thrower

Zacharias

2017

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

We present temperature programmed desorption (TPD) measurements of CO, CH 4 , O 2 and CO 2 from the forsterite(010) surface in the sub-monolayer and multilayer coverage regimes. In the case of CO, CH 4 and O 2 , multilayer growth begins prior to saturation of the monolayer peak, resulting in two clearly distinguishable desorption peaks. On the other hand a single peak for CO 2 is observed which shifts from high temperature at low coverage to low temperature at high coverages, sharpening upon multilayer formation. The leading edges are aligned for all the molecules in the multilayer coverage regime indicating zero order desorption. We have extracted multilayer desorption energies for these molecules using an Arrhenius analysis. For sub-monolayer coverages, we observe an extended desorption tail to higher temperature. Inversion analysis has been used to extract the coverage dependent desorption energies in the sub-monolayer coverage regime, from which we obtain the desorption energy distribution. We found that owing to the presence of multiple adsorption energy sites on the crystalline surface the typical desorption energies of these small molecules are significantly larger than obtained in previous measurements for several other substrates. Therefore molecules bound to crystalline silicate surfaces may remain locked in the solid state for a longer period of time before desorption into the gas phase.

show abstract

Section: Experimental Methodsmentioning

confidence: 94%

Thermal desorption of astrophysically relevant molecules from forsterite(010)

Suhasaria¹,

Thrower

Zacharias

2017

Monthly Notices of the Royal Astronomical Society

Self Cite

View full text Add to dashboard Cite

show abstract

“…H 2 O, CO 2 , CH 4 , etc.) over silicate grains in the interstellar medium are typically on the order of 0.1 eV (Seki & Hasegawa 1983;Suhasaria et al 2015Suhasaria et al , 2017, though energies >1 eV are also possible for metallic surfaces (e.g. desorption of potassium from a nickel surface ; B laszczyszyn et al 1995).…”

Section: Carmamentioning

confidence: 99%

Sedimentation Efficiency of Condensation Clouds in Substellar Atmospheres

Gao

Marley

Ackerman

2018

ApJ

View full text Add to dashboard Cite

Condensation clouds in substellar atmospheres have been widely inferred from spectra and photometric variability. Up until now, their horizontally averaged vertical distribution and mean particle size have been largely characterized using models, one of which is the eddy diffusion-sedimentation model from Ackerman & Marley (2001) that relies on a sedimentation efficiency parameter, f sed , to determine the vertical extent of clouds in the atmosphere. However, the physical processes controlling the vertical structure of clouds in substellar atmospheres are not well understood. In this work, we derive trends in f sed across a large range of eddy diffusivities (K zz ), gravities, material properties, and cloud formation pathways by fitting cloud distributions calculated by a more detailed cloud microphysics model. We find that f sed is dependent on K zz , but not gravity, when K zz is held constant. f sed is most sensitive to the nucleation rate of cloud particles, as determined by material properties like surface energy and molecular weight. High surface energy materials form fewer, larger cloud particles, leading to large f sed (>1), and vice versa for materials with low surface energy. For cloud formation via heterogeneous nucleation, f sed is sensitive to the condensation nuclei flux and radius, connecting cloud formation in substellar atmospheres to the objects' formation environments and other atmospheric aerosols. These insights could lead to improved cloud models that help us better understand substellar atmospheres. For example, we demonstrate that f sed could increase with increasing cloud base depth in an atmosphere, shedding light on the nature of the brown dwarf L/T transition.

show abstract

“…A number of laboratory experiments studying the desorption of ices from dust surfaces have been performed. Here, we refer the reader to a review paper (Burke & Brown 2010) and recent studies (Noble et al 2012;Dawley, Pirim, & Orlando 2014;Shi, Grieves, & Orlando 2015;Suhasaria, Thrower, & Zacharias 2017). However, as it was discussed above, dust in dense molecular clouds, planet-forming disks, and comets is mixed with molecular ices.…”

Section: Introductionmentioning

confidence: 98%

Temperature Programmed Desorption of Water Ice from the Surface of Amorphous Carbon and Silicate Grains as Related to Planet-forming Disks

Потапов¹,

Jäger²,

Henning³

2018

ApJ

View full text Add to dashboard Cite

Understanding the history and evolution of small bodies, such as dust grains and comets, in planet-forming disks is very important to reveal the architectural laws responsible for the creation of planetary systems. These small bodies in cold regions of the disks are typically considered as mixtures of dust particles with molecular ices, where ices cover the surface of a dust core or are actually physically mixed with dust. Whilst the first case, ice-on-dust, has been intensively studied in the laboratory in recent decades, the second case, ice-mixed-withdust, present uncharted territory. This work is the first laboratory study of the temperatureprogrammed desorption (TPD) of water ice mixed with amorphous carbon and silicate grains.We show that the kinetics of desorption of H2O ice depends strongly on the dust/ice mass ratio, probably, due to the desorption of water molecules from a large surface of fractal clusters composed of carbon or silicate grains. In addition, it is shown that water ice molecules are differently bound to silicate grains in contrast to carbon. The results provide a link between the structure and morphology of small cosmic bodies and the kinetics of desorption of water ice included in them.

show abstract

Thermal desorption of ammonia from crystalline forsterite surfaces

Cited by 28 publications

References 69 publications

Thermal desorption of astrophysically relevant molecules from forsterite(010)

Thermal desorption of astrophysically relevant molecules from forsterite(010)

Sedimentation Efficiency of Condensation Clouds in Substellar Atmospheres

Temperature Programmed Desorption of Water Ice from the Surface of Amorphous Carbon and Silicate Grains as Related to Planet-forming Disks

Contact Info

Product

Resources

About