Dust as interstellar catalyst - I. Quantifying the chemical desorption process

Free Access

Table 1

Experimental chemical desorption efficiencies for different reactions on three different surfaces (np-ASW, amorphous silicate, and oxidized graphite).

Experiments	Surface	Coverage	Method		Reaction	Desorbing	ΔH_R	Experimental CD efficiency			Theoretical CD efficiency
	temperature	range	DED	TPD		product

								np-ASW	Amorphous	Oxidized
									silicate	HOPG
	(K)	(ML)					eV	%	%	%	%

					O+H	OH	4.44	25 ± 15^*	–	50 ± 25^*	39
[O+H]	10	<1	^√	^√	OH+H	H₂O	5.17	30 ± 15^*	–	50 ± 25^*	27
					OH+H	H₂O	5.17	< 40 ± 20 ^a	< 70 ± 20 ^a	< 80 ± 20 ^b	27
					O₂+H	O₂H	2.24	<8^*	10 ± 10 ^b	–	1.4
					O₂H+H	H₂O₂	3.69	<8^*	<5^b	–	0.5
					O₂H+H	2 OH	1.47	<8^*	<5^b	–	0.3
[O₂+H]	10	0.5-1	^√	^√	H₂O₂+H	H₂O+OH	2.95	<5^*	<5^b	–	2.1
					O₃+H	O₂+OH	3.33	–	<10^b	<8^*	8
[O₃+H]	10 and 45	0.5-1	^√	^√	OH+H	H₂O	5.17	–	80 ± 20 ^b	–	27
					O+O	O₂	5.16	<5^c	40 ± 10 ^# ^, ^d	80 ± 10 ^# ^, ^e	68
[O+O]	8 to 25	<1	^√	^√	O₂+O	O₃	1.1	<5^c	<5^d	<5^e	0
[N+N]	10	<1	^√	^√	N+N	N₂	9.79	>50^&^*	>70^&^*	>70^&^*	89
					CO+H	HCO	0.66	–	–	10 ± 8 ^*	0.7
					HCO+H	CO+H₂	3.85	–	–	40 ± 20 ^*	47
[CO+H]	10	0.8–2.5	^√	^√	HCO+H	H₂CO	3.91	–	–	<8^*	7
					H₂CO+H	CH₃O	0.88	–	–	<8^*	0
					H₂CO+H	HCO+H₂	0.61	–	–	10 ± 5 ^*	0
					HCO+H	CO+H₂	3.85	–	–	40 ± 20 ^*	47
					HCO+H	H₂CO	3.91	–	–	10 ± 5 ^*	7
[H₂CO+H]	10 and 55	0.8–2	^√	^√	CH₃O+H	CH₃OH	4.56	<8^*	–	<8^*	2.3
[Ar+H]	10	1	^√	^√	Ar+H	Ar		–	<5^*	–
[NO+H/O/N]	10	0.5–5	X	^√	many	many		<8^*	<8^*	<8^*
[CO+O]	10	0.5–4	^√	^√	CO+O	CO₂	5.51	<5^*	–	<5^*	22
[H₂CO+O]	10 and 55	0.8–2	X	^√	H₂CO+O	CO₂+H₂	5.45	<10^*	–	<10^*	8
[CH₃OH+H]	10	0.5–2	^√	^√	CH₃OH+H	CH₃OH		<8^*	–	<8^*
[CH₃OH+O]	10	0.5–2	^√	^√	CH₃OH+O	CH₃OH		<8^*	–	<8^*

Notes. For the cases in which we were unable to quantitatively measure the CD efficiency, we provide upper or lower limits. We list theoretical CD efficiencies calculated for an oxidized graphite. Surface temperature indicates deposition temperature of both reactants. Coverage range indicates the coverage of molecular ice growth before atom irradiation; in the case of experiments performed only with atomic species, coverage range indicates the total amount of species placed on the surface. ^√ and X are used to indicate whether the experimental procedure (DED or TPD) was used or not;

^(#)

CD decreases as a function of coverage;

^(&)

experiments performed with excited particles (see Minissale 2014);

^(a)

Chaabouni et al. (2012);

^(b)

Dulieu et al. (2013);

^(c)

Minissale et al. (2013);

^(d)

Minissale et al. (2014);

^(e)

Minissale & Dulieu (2014);

^(*)

this work.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.