3.2 Monohydrated Core Ion NO
−
3 HNO 3
ð
Þ 2 H 2 O
Ninety different structures were obtained in the conformational searching for
NO
−
3 HNO 3
ð
Þ 2 H 2 O. We classified these conformers into four groups, A−D,
according to the structure of NO
−
3 HNO 3
ð
Þ 2 and/or the hydrogen-bonded structure
between H 2 O and other fragments. The group A (B) contains 23 (56) kinds of
conformers which have a hydrogen-bonded structure between H 2 O and the core
ions of the group α (β). In these two groups, H 2 O is located outside of the cluster
(H 2 O-attached form). In the group C containing ten conformers, the H 2 O molecule
is located at the center of a cluster (H 2 O-embedded form), and has two or three HBs
with NO
−
3 and HNO 3 fragments. The group D contains only one conformer in
which the proton transfer is occurred from H 2 O to NO
−
3 as OH
− HNO 3
ð
Þ 3 having
C 3 symmetry. The lowest energy geometries in each group and those relative
energies at 0 K are shown in Fig. 4. As seen in Fig. 4, the most stable structure of
NO
−
3 HNO 3
ð
Þ 2 H 2 O at 0 K is the H 2 O-embedded form of the group C. Drenck and
(a)
(b)
Fig. 3 The temperature dependence of relative abundances of NO
−
3 HNO 3
ð
Þ 2 conformers: a p i
values defined in Eq. (1) of all conformers (in the common logarithmic scale), b the sum of p i
values in each group (in percent figures). The numbers of conformers in the group α and β are 3
and 12, respectively
198
A. Ueda et al.
−
3 HNO 3
ð
Þ 2 H 2 O
Ninety different structures were obtained in the conformational searching for
NO
−
3 HNO 3
ð
Þ 2 H 2 O. We classified these conformers into four groups, A−D,
according to the structure of NO
−
3 HNO 3
ð
Þ 2 and/or the hydrogen-bonded structure
between H 2 O and other fragments. The group A (B) contains 23 (56) kinds of
conformers which have a hydrogen-bonded structure between H 2 O and the core
ions of the group α (β). In these two groups, H 2 O is located outside of the cluster
(H 2 O-attached form). In the group C containing ten conformers, the H 2 O molecule
is located at the center of a cluster (H 2 O-embedded form), and has two or three HBs
with NO
−
3 and HNO 3 fragments. The group D contains only one conformer in
which the proton transfer is occurred from H 2 O to NO
−
3 as OH
− HNO 3
ð
Þ 3 having
C 3 symmetry. The lowest energy geometries in each group and those relative
energies at 0 K are shown in Fig. 4. As seen in Fig. 4, the most stable structure of
NO
−
3 HNO 3
ð
Þ 2 H 2 O at 0 K is the H 2 O-embedded form of the group C. Drenck and
(a)
(b)
Fig. 3 The temperature dependence of relative abundances of NO
−
3 HNO 3
ð
Þ 2 conformers: a p i
values defined in Eq. (1) of all conformers (in the common logarithmic scale), b the sum of p i
values in each group (in percent figures). The numbers of conformers in the group α and β are 3
and 12, respectively
198
A. Ueda et al.