Photolysis of solid NH{sub 3} and NH{sub 3}-H{sub 2}O mixtures at 193 nm

Journal Article · Tue Dec 07 00:00:00 EST 2010 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3506577· OSTI ID:21559957

Loeffler, M J ^[1]; Baragiola, R A ^[2]

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1. Astrochemistry Laboratory, NASA Goddard Space Flight Center, Code 691, Greenbelt, Maryland 20771 (United States)
2. Laboratory for Atomic and Surface Physics, Engineering Physics, University of Virginia, Charlottesville, Virginia 22904 (United States)

We have studied UV photolysis of solid ammonia and ammonia-dihydrate samples at 40 K, using infrared spectroscopy, mass spectrometry, and microgravimetry. We have shown that in the pure NH{sub 3} sample, the main species ejected are NH{sub 3}, H{sub 2}, and N{sub 2}, where the hydrogen and nitrogen increase with laser fluence. This increase in N{sub 2} ejection with laser fluence explains the increase in mass loss rate detected by a microbalance. In contrast, for the ammonia-water mixture, we see very weak signals of H{sub 2} and N{sub 2} in the mass spectrometer, consistent with the very small mass loss during the experiment and with a <5% decrease in the NH{sub 3} infrared absorption bands spectroscopy after a fluence of {approx}3 x 10{sup 19} photons/cm{sup 2}. The results imply that ammonia-ice mixtures in the outer solar system are relatively stable under solar irradiation.

• OSTI ID: 21559957
• Journal Information: Journal of Chemical Physics, Vol. 133, Issue 21; Other Information: DOI: 10.1063/1.3506577; (c) 2010 American Institute of Physics; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
ABSORPTION SPECTROSCOPY
AMMONIA
CHEMICAL ANALYSIS
HYDRATES
HYDROGEN
INFRARED SPECTRA
IRRADIATION
LASERS
MASS SPECTROMETERS
MASS SPECTROSCOPY
MICROBALANCES
MIXTURES
NITROGEN
PHOTOLYSIS
PHOTONS
SOLAR SYSTEM
SOLIDS
ULTRAVIOLET RADIATION
WATER
BALANCES
BOSONS
CHEMICAL REACTIONS
DECOMPOSITION
DISPERSIONS
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
ELEMENTS
HYDRIDES
HYDROGEN COMPOUNDS
MASSLESS PARTICLES
MEASURING INSTRUMENTS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATIONS
SORPTION
SPECTRA
SPECTROMETERS
SPECTROSCOPY
WEIGHT INDICATORS