# Photodesorption of H2O, HDO, and D2O ice and its impact on fractionation

@article{Arasa2015PhotodesorptionOH,
title={Photodesorption of H2O, HDO, and D2O ice and its impact on fractionation},
author={Carina Arasa and Jesper Koning and G J Kroes and Catherine Walsh and Ewine F. van Dishoeck Gorlaeus Laboratories and Leiden Institute of Chemistry and Leiden University and P. O. Box 9502 and 2300 RA Leiden and The Netherlands. and Leiden Observatory and P. O. Box 9513 and Max Planck Institute for Extraterrestrial Physics and 1 Giessenbachstrasse and 85748 Garching and H Germany},
journal={arXiv: Astrophysics of Galaxies},
year={2015}
}
• Published 1 March 2015
• Chemistry, Physics
• arXiv: Astrophysics of Galaxies
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 of water ice. We present fitting formulae for implementation in astrochemical models using photodesorption efficiencies for all water ice isotopologues obtained using classical molecular dynamics simulations. We investigate if the gas-phase HDO/H2O ratio…
27 Citations

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## References

SHOWING 1-10 OF 65 REFERENCES
PHOTODESORPTION OF ICES. II. H2O AND D2O
• Physics
• 2008
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
Isotope effects on the photodesorption processes of X2O (X = H,D) and HOD ice.
• Chemistry, Physics
The Journal of chemical physics
• 2013
Reasoning based on the X2O phonon frequencies associated with the librational modes and energy transfer efficiencies explain why the OX radical photodesorption probabilities are noticeably larger if the Ox radical desorbs from a D2O ice system than from an H2OIce system.
Molecular-dynamics study of photodissociation of water in crystalline and amorphous ices.
• Physics, Chemistry
The Journal of chemical physics
• 2006
The outcomes of photodissociation in crystalline and amorphous ices are overall similar, but with some intriguing differences in detail.
Molecular dynamics simulations of D2O ice photodesorption.
• Chemistry, Physics
The Journal of chemical physics
• 2011
Molecular dynamics (MD) calculations have been performed to study the ultraviolet (UV) photodissociation of D(2)O in an amorphous D(2)O ice surface at 10, 20, 60, and 90 K, in order to investigate
Photodesorption of water ice - A molecular dynamics study
• Physics
• 2008
Context. 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
Molecular dynamics simulations of the ice temperature dependence of water ice photodesorption
• Physics, Chemistry
• 2010
The ultraviolet (UV) photodissociation of amorphous water ice at different ice temperatures is investigated using molecular dynamics (MD) simulations and analytical potentials. Previous MD
The HDO/H2O Ratio in Gas in the Inner Regions of a Low-mass Protostar
• Geology, Physics
• 2010
The HDO/H2O abundance ratio is thought to be a key diagnostic for the evolution of water during the star and planet formation process and thus for its origin on Earth. We here present
Interstellar Ices as Witnesses of Star Formation: Selective Deuteration of Water and Organic Molecules Unveiled
• Physics
• 2011
Observations of star-forming environments revealed that the abundances of some deuterated interstellar molecules are markedly larger than the cosmic D/H ratio of 10{sup -5}. Possible reasons for this
Water Ice Formation and the o/p Ratio
• F. Dulieu
• Physics
Proceedings of the International Astronomical Union
• 2011
Abstract Water is observed in many astrophysical environments in both gas and solid phase. Water ice, for its specific properties, is probably the most important template that structures the
Deuterium Fractionation in Protoplanetary Disks
• Physics, Geology
• 1999
We investigate the chemistry of deuterium-bearing molecules in outer regions of protoplanetary disks, where comets may form. We find that molecules formed in the disk have higher D/H ratios (by which