Micromeritics ASAP 2460 - Page 343

ASAP 2460 Operator’s Manual Appendix C
246-42800-01 - Aug 2013 C-19
All new pores opened in this interval are represented by one pore having a length-
weighted average pore diameter and a corresponding length sufficient to account for
the required volume of adsorbate. The weighted average pore diameter is calculated
as:
D
avg,k
is the diameter of a pore which would have a surface area that is the average of
the areas for pores radius Rc
k
and Rc
k+1
, if its length was the mean of the lengths at
those radii.
The relative pressure corresponding to D
avg,k
is calculated as:
The thickness of the adsorbed layer at this pressure is calculated as:
The decrease in thickness of the wall layer by desorption from the walls of new pores
during the lower portion of the pressure interval is calculated as:
The cross-sectional area of the newly opened pores is calculated as:
The length of the newly opened pores is calculated as:
D
avg k
2 Rc
k
Rc
k1+
+Rc
k
Rc
k1+

Rc
k
2
Rc
k1+
2
+
---------------------------------------------------------------------------
=
P
avg k
1–
2A–
1 F+D
avg k

---------------------------------------
ln=
Tw
avg k
HP1
HP2
P
avg k
ln
-------------------------
HP3
=
Td Tw
avg k
Tw
i1+
–=
CSAc
k
D
avg k
2
----------------
Td+
2
10
16–
cm
2
Å
2
-------------------------



=
LP
k
Vc
i
CSAc
k
----------------
=