Micromeritics TRISTAR II PLUS Operator's Manual page 133

D
ATA ANALYSES BY THE
In general, this method visualizes the incremental decomposition of an experimental isotherm,
starting at the highest relative pressure or pore size. At each step the quantity of adsorptive
involved is divided between pore-emptying and film-thinning processes and is accounted for
totally. This computational algorithm frequently leads to inconsistencies when carried to small
mesopore sizes. If the thickness curve used is too steep, ultimately it will predict a larger
increment of adsorptive for a given pressure increment than is actually observed. The algorithm
must stop since a negative pore volume is nonphysical. Accumulated error results in the
calculation of a too large volume of (possibly nonexistent) small pores if the thickness curve used
underestimates film thinning.
TriStar II Plus Operator Manual
303-42800-01 (Rev M ) — Sep 2023
BJH
METHOD
Evaluate Report Results
7 - 17