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Fig. 8 Distribution of the final translational energy (in eV) of O(
3
P) for each angle of incidence
(
0
,30
,45
, and 60
)
y
¼
i
able to absorb energy upon bombardment by a nonreactive atom. Overall there is a
broad distribution of final translational energies from the more glancing angle of
60
, and on average about half the 5.0 eV initial energy is transferred to the liquid.
For more direct angles of incidence, nearly all the final translational energy is below
1.0 eV, indicating that multiple collisions play an important role. Figure
8
shows the
corresponding results for inelastically scattered O atoms. (No 0
data are presented
because almost all the incident Os undergo reaction for this angle.) For an incident
angle of 60
, there is a very similar distribution of final translational energies for O as
was found with Ar. This is likely due to the fact that at this glancing angle there is
very little penetration of the surface (0.94
˚
0.68
˚
for O on average),
thus minimizing the number of collisions and leaving the incident atom mostly
unchanged. For the more direct collisions at 30
and 45
, the scattered O has more
translational energy than Ar, as if the larger, heavier Ar atom is a “softer” atom
losing more energy to the liquid. The distribution of final translational energy from
the OH desorption product is depicted in Fig.
9
. There is a slight decrease (~0.5 eV)
in the translational energies of the OH product in comparison to the inelastically
scattered O, with similar distributions between the various angles of incidence. Most
of the OH products are fromH abstraction at the C-H groups on the ethyl and methyl
substituents on the imidazolium ring, which are sticking up out of the surface. On
average, at 60
incidence angle, both O and OH scatter from [emim][NO
3
], as we
found with our QM/MM-MDmodel, with about half the initial translational energy;
this coincides with the experimentally determined final translational energy of O and
OH scattering from [emim][NTf
2
]. Other nascent products, which are not shown
for Ar and
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