Chemistry Reference
In-Depth Information
1.2
ε = -0.001
200
1.0
ε = -11
0.8
150
0.6
100
ε = -0.25
0.4
ε = -8.5
50
0.2
ε = -0.5
ε = -0.75
ε = -1.0
ε = -6.0
0.0
0
ε = -0.999
-0.2
0.0
0.2
0.4
0.6
0.8
1.0
0.0
0.2
0.4
0.6
0.8
1.0
x
A
x
A
FIGURE 2.16
The measure of the deviation from an SI solution Δ
AB
for the same system
as in Figure 2.8.
from the case of
G
AA
and
G
BB
is that
G
AB
converges to the same value at both ends
of the composition range.
Next, we turn to the quantity Δ
AB
shown in Figure 2.16, which is a measure of the
deviations from an SI solution. As expected, for ε = -1, we find that Δ
AB
= 0. Since
the particles are identical, they form an SI
solution. For |ε| ≤ 1, Δ
AB
is the larger dis-
similarity between the particles, that is, the smaller the value of |ε| ≤ 1. However, for
|ε| ≥ 1, we observe larger positive deviations from SI. The deviations seem to get very
large at both ends of the composition range.
In Figure 2.17, we present the limiting coefficient of the PS of A with respect to
A and B. These quantities are of interest in their own right. First, we note that for
|ε| = 1 values of
δ
AA
0
are all zero and independent of
x
A
. This result is due to the fact
15
0.20
ε = -0.001
ε = -11
0.15
10
0.10
ε = -8.5
ε = -0.25
5
ε = -0.5
0.05
ε = -6.0
ε = -0.75
ε = -1.0
0
ε = -0.999
0.00
0.0
0.2
0.4
0.6
0.8
1.0
0.0
0.2
0.4
0.6
0.8
1.0
x
A
x
A
FIGURE 2.17
The limiting coefficient of the preferential solvation of A with respect to A
and B for the same system as in Figure 2.8.
