Micromeritics TriStar II 3020 - Interaction Parameter

TriStar II 3020 Appendix C
302-42828-01 - Dec 2012 C-23
Interaction Parameter
A
S
6 MC
2

S

A


S

S
------

A

A
------
+
-----------------------------------------------
=
A
A
3 MC
2

A

A

2
-----------------------------------------------
=
IP N
A
A
A
N
S
A
S
+=
The interaction parameter (IP) results from the following calculations:
The Kirkwood-Muller dispersion coefficients -
where
MC
2
= kinetic energy of electron (0.8183 x 10
-6
erg)

S
= polarizability of sample atoms (cm
3
)

A
= polarizability of gas molecule (cm
3
)

S
= diamagnetic susceptibility of sample atom (cm
3
)

A
= diamagnetic susceptibility of gas molecule (cm
3
)
where:
N
A
= number of gas molecules/cm
2
at monolayer from the Horvath-Kawazoe Physi-
cal Properties dialog
N
S
= number of sample atoms/cm
2
from the Horvath-Kawazoe Physical Properties
dialog 
Refer to Interaction Parameter Components later in this Appendix for recommended values.