Dubinin-Radushkevich - Micromeritics TriStar II 3020 Operator's Manual

TriStar II 3020

Dubinin-Radushkevich

The Dubinin-Radushkevich
V  
log =
where:
V =
Vo =
Po =
P =
B =

=
T =
For each point designated for Dubinin-Radushkevich calculations, the following calculations are done:
LV = log (V)

Po
------ -
= log
LP

P
The intercept, log(Vo) can be found by performing a least-squares fit on the (LP,LV) designated pairs
where LP is the independent variable and LV is the dependent variable. Assuming the adsorption of
gas is restricted to a monolayer, Vo is the monolayer capacity. Based on this assumption, the following
are calculated:
a.) Slope (S cm
b.) Y-intercept (YI cm
c.) Error of the slope (S
d.) Error of the y-intercept (YI
e.) Correlation coefficient
Using the results of the above calculations, the following can be calculated:
Monolayer Capacity (cm
YI
Vo = 10
302-42828-01 - Dec 2012
13
equation is as follows:
2 2

B T
Po
  
---------------
log – log ------ -
Vo

P
volume adsorbed at equilibrium pressure (cm
the micropore capacity (cm
saturation vapor pressure of gas at temperature T (mmHg)
equilibrium pressure (mmHg)
a constant
the affinity coefficient of analysis gas relative to Po gas
(for this application  is taken to be 1)
analysis bath temperature (K), from the Po and Temperature Options dialog
2


3
/g STP)
3
/g STP)
3
cm /g STP)
ERR
3
cm
ERR
3
/g STP):
3
/g STP)
/g STP)
Appendix C
3
/g STP)
C-27