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squalane, which makes sense since the ionic liquid has a smaller fraction of
abstractable hydrogens. There is a small chance, 0.13, that the O does not react
and bounces back from the [emim][NO
3
] surface; inelastic collisions of this nature
with O
squalane occur more often, with an overall average probability of 0.23.
In the O
þ
[emim][NO
3
] collisions, more than half of the products desorb from
the surface during our simulation time, as shown in Table
1
. This is in contrast to the
Ar collision study where the probability of non-Ar containing products was 0.17. As
with the nonreactive study, the O collisions also cause one to three proton transfers
(see Table
2
). Interestingly, a similar portion of HNO
3
, emim, and
emim
þ
[NO
3
]
desorb from the [emim][NO
3
] surface as compared to the nonreactive study; HNO
2
is an additional product found in the O scatter data. It is likely that the proton
transfer event is responsible for these species desorbing from the [emim][NO
3
]
surface. The H abstraction channel, which occurs predominantly at the ethyl or
methyl sites on the imidazolium ring, forms OH and has a desorption probability of
0.04. Nearly half of all the OH created desorbs from the surface by the end of the
simulation (7.3 ps). In squalane, around 80% of the OH exits the surface. This is
reflective of the differences in the surface density and the amount of diffusion that is
possible within these two liquids. It must be noted that no charged species were
found to desorb, which is not surprising because they would inevitably be attracted
back to either the cations or anions at the surface.
In connection with the experimental observables that Minton et al. have measured
for the similar reaction (O + [emim][NTf
2
]), we also report the translational energy
distribution of the inelastically scattered atoms as well as of the major molecular
products. Figure
7
provides a basis for understanding how the [emim][NO
3
] liquid is
þ
Fig. 7 Distribution of the final translational energy (in eV) of Ar for each angle of incidence
(
y
¼
0
,30
,45
, and 60
)
i
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