Ultraviolet photodesorption from water ice

Westley, M. S.; Baragiola, R. A.; Johnson, R. E.; Baratta, G. A.

doi:10.1016/0032-0633(95)00088-m

Cited by 141 publications

(113 citation statements)

References 10 publications

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“…Following the ultraviolet photolysis of H 2 O 2 in various rare-gas matrices at 7.5 K, a ͑H 2 O-O͒ complex was formed from the recombination of OH radicals, while the primary formations of H 2 O+O͑ 1 D͒ or O͑ 3 P J ͒ have not been established from the photodissociation of gaseous H 2 O 2 at 124-254 nm. 11,12 Experimental works on photon-or electron-stimulated desorption ͑ESD͒ of species from water ice have also been reported, [13][14][15][16][17][18][19][20] In the present study, using pulsed 157 nm ͑181 kcal/ mol͒ laser radiation the desorptions of electronically excited O͑ 1 D͒ atoms via the primary and secondary photoprocesses from ASW at 90 K have been directly confirmed by REMPI. Translationally and internally excited OH formation mechanisms were also discussed since hot OH is a plausible source for the oxygen atom.…”

Section: H 2 O + H → H + Oh ͑2͒supporting

confidence: 68%

Formation mechanisms of oxygen atoms in the O(D21) state from the 157nm photoirradiation of amorphous water ice at 90K

Hama

Yabushita

Yokoyama

et al. 2009

The Journal of Chemical Physics

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Vacuum ultraviolet photolysis of water ice in the first absorption band was studied at 157 nm. Translational and internal energy distributions of the desorbed species, O͑ 1 D͒ and OH͑v =0,1͒, were directly measured with resonance-enhanced multiphoton ionization method. Two different mechanisms are discussed for desorption of electronically excited O͑ 1 D͒ atoms from the ice surface. One is unimolecular dissociation of H 2 O to H 2 +O͑ 1 D͒ as a primary photoprocess. The other is the surface recombination reaction of hot OH radicals that are produced from photodissociation of hydrogen peroxide as a secondary photoprocess. H 2 O 2 is one of the major photoproducts in the vacuum ultraviolet photolysis of water ice.

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Section: H 2 O + H → H + Oh ͑2͒supporting

confidence: 68%

Formation mechanisms of oxygen atoms in the O(D21) state from the 157nm photoirradiation of amorphous water ice at 90K

Hama

Yabushita

Yokoyama

et al. 2009

The Journal of Chemical Physics

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“…In the case of normal 1 We need to consider that the discharge lamps are not monochromatic, with a spectrum of the emitted radiation depending on experimental conditions, such as pressure in the discharge tube and gas mixture ratio. For example, the operating conditions adopted by Westley et al (1995b;see their Fig. 1) produce negligible UV radiation outside the Lyman-α line; on the other hand, the Lyman-α emission accounts for at most 5% of the total lamp intensity in the operating conditions used by Cottin et al (2003;see their Fig.…”

Section: Experimental Methodsmentioning

confidence: 99%

CO$\mathsf{_{2}}$ synthesis in solid CO by Lyman-α photons and 200 keV protons

Loeffler

Baratta²,

Palumbo³

et al. 2005

A&A

139

150

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Abstract.We have studied the synthesis of carbon dioxide from solid carbon monoxide at 16 K induced by photolysis with Lyman-α photons and by irradiation with 200 keV protons to quantitatively compare the effects of photolysis and ion irradiation on CO ice and to determine the importance of these processes in interstellar ice grains. The CO and CO 2 concentrations during irradiation of an initially pure CO film evolve with fluence to a saturation value, a behaviour that is explained by a two-state model. Our results indicate that the initial CO 2 production rates for both radiation processes are similar when normalized to the absorbed energy and that the solid CO 2 abundance observed in the interstellar ices cannot be explained only by radiolysis and photolysis of pure solid CO.

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“…1,2 Oxygen molecule is known to be a product when water ice is irradiated with photons, electrons, or with energetic ions. [3][4][5][6] Westley et al 7,8 observed desorption of H 2 , O 2 , and H 2 O by a quadrupole mass spectrometer ͑QMS͒ during vacuum ultraviolet ͑VUV͒ irradiation of water ice at 35-100 K with mainly Lyman-␣ photons ͑ Х 121 nm͒. Öberg et al 9 used a VUV lamp ͑118 nmՅ Յ177 nm͒ to irradiate water ice at 18-100 K, and detected OH, H 2 , O 2 , and H 2 O as desorbing species by QMS.…”

Section: Introductionmentioning

confidence: 99%

Role of OH radicals in the formation of oxygen molecules following vacuum ultraviolet photodissociation of amorphous solid water

Hama

Yokoyama

Yabushita

et al. 2010

The Journal of Chemical Physics

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Photodesorption of O 2 ͑X 3 ⌺ g − ͒ and O 2 ͑a 1 ⌬ g ͒ from amorphous solid water at 90 K has been studied following photoexcitation within the first absorption band at 157 nm. Time-of-flight and rotational spectra of O 2 reveal the translational and internal energy distributions, from which production mechanisms are deduced. Exothermic and endothermic reactions of OH+ O͑ 3 P͒ are proposed as plausible formation mechanisms for O 2 ͑X 3 ⌺ g − and a 1 ⌬ g ͒. To examine the contribution of the O͑ 3 P͒ +O͑ 3 P͒ recombination reaction to the O 2 formation following 157 nm photolysis of amorphous solid water, O 2 products following 193 nm photodissociation of SO 2 adsorbed on amorphous solid water were also investigated.

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Ultraviolet photodesorption from water ice

Cited by 141 publications

References 10 publications

Formation mechanisms of oxygen atoms in the O(D21) state from the 157nm photoirradiation of amorphous water ice at 90K

Formation mechanisms of oxygen atoms in the O(D21) state from the 157nm photoirradiation of amorphous water ice at 90K

CO$\mathsf{_{2}}$ synthesis in solid CO by Lyman-α photons and 200 keV protons

Role of OH radicals in the formation of oxygen molecules following vacuum ultraviolet photodissociation of amorphous solid water

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