Chemistry Reference
In-Depth Information
Fig. 2 Coexistence curve for CO
2
in the temperature density plane (a), vapor pressure at coexis
tence (b), and surface tension versus temperature (c).
Dashed curves
are the experimental data,
while
solid curves
describe the prediction of the simple (truncated and shifted) LJ model (
5
), where
the critical temperature and density are adjusted to coincide with experiment to fix the two
parameters
e
ss
and
s
ss
, as for Fig.
1
.
Stars
and
crosses
denote the results of [
131
] for the parameter
q
ð
T
c
Þ
that controls the strength of the quadrupolar interaction being chosen as
q
ð
T
c
Þ
0
:
387 or
q
T
c
Þ
0
:
47, respectively (see Sect.
2.2
).
Plus symbols
and
triangles
are the result of atomistic
models called EPM and EPM2 [
146
].
Small circles near the pluses
are the results for flexible
monomers [
146
], which give essentially the same results for the thermodynamic properties as the
model for rigid molecules.
Big circles
and
squares
are simulation results [
156
] for two ab initio
potentials [
146
,
150
]. Note that the interaction parameters of the EPM2 models have similarly been
rescaled to fit the critical density and temperature of the experiment as done in Fig.
1
, and that
no prediction for the liquid vapor surface tension from the atomistic models is available. From
Mognetti et al. [
131
]
ð
