MOSCED ist ein thermodynamisches Modell zur Abschätzung von Grenzaktivitätskoeffizienten (auch als Aktivitätskoeffizienten bei unendlicher Verdünnung bekannt).
ln
γ
2
∞
=
ν
2
R
T
[
(
λ
1
−
λ
2
)
2
+
q
1
2
q
2
2
(
τ
1
T
−
τ
2
T
)
2
ψ
1
+
(
α
1
T
−
α
2
T
)
(
β
1
T
−
β
2
T
)
ξ
1
]
+
d
12
{\displaystyle \ln \gamma _{2}^{\infty }={\frac {\nu _{2}}{RT}}\left[\left(\lambda _{1}-\lambda _{2}\right)^{2}+{\frac {q_{1}^{2}q_{2}^{2}\left(\tau _{1}^{T}-\tau _{2}^{T}\right)^{2}}{\psi _{1}}}+{\frac {\left(\alpha _{1}^{T}-\alpha _{2}^{T}\right)\left(\beta _{1}^{T}-\beta _{2}^{T}\right)}{\xi _{1}}}\right]+d_{12}}
d
12
=
ln
(
ν
2
ν
1
)
a
a
+
1
+
(
ν
2
ν
1
)
a
a
{\displaystyle d_{12}=\ln \left({\frac {\nu _{2}}{\nu _{1}}}\right)^{aa}+1+\left({\frac {\nu _{2}}{\nu _{1}}}\right)^{aa}}
a
a
=
0.953
−
0.002314
(
(
τ
2
T
)
2
+
α
2
T
β
2
T
)
{\displaystyle aa=0.953-0.002314\left(\left(\tau _{2}^{T}\right)^{2}+\alpha _{2}^{T}\beta _{2}^{T}\right)}
α
T
=
α
(
293
K
T
)
0.8
{\displaystyle \alpha ^{T}=\alpha \left({\frac {293K}{T}}\right)^{0.8}}
,
β
T
=
β
(
293
K
T
)
0.8
{\displaystyle \beta ^{T}=\beta \left({\frac {293K}{T}}\right)^{0.8}}
,
τ
T
=
τ
(
293
K
T
)
0.4
{\displaystyle \tau ^{T}=\tau \left({\frac {293K}{T}}\right)^{0.4}}
ψ
1
=
P
O
L
+
0.002629
α
1
T
β
1
T
{\displaystyle \psi _{1}=POL+0.002629\alpha _{1}^{T}\beta _{1}^{T}}
ξ
1
=
0.68
(
P
O
L
−
1
)
+
[
3.4
−
2.4
exp
(
−
0.002687
(
α
1
β
1
)
1.5
)
]
(
293
K
/
T
)
2
{\displaystyle \xi _{1}=0.68\left(POL-1\right)+\left[3.4-2.4\exp \left(-0.002687\left(\alpha _{1}\beta _{1}\right)^{1.5}\right)\right]^{\left(293K/T\right)^{2}}}
P
O
L
=
q
1
4
[
1.15
−
1.15
exp
(
−
0.002337
(
τ
1
T
)
3
)
]
+
1
{\displaystyle POL=q_{1}^{4}\left[1.15-1.15\exp \left(-0.002337\left(\tau _{1}^{T}\right)^{3}\right)\right]+1}