Micromeritics TRISTAR II PLUS User Manual

NLDFT ADVANCED PSD REPORT
The NLDFT Advanced PSD report allows for more advanced computation of the pore size
distribution of a material using two separate analyses and two non-local DFT models.
The NLDFT Advanced PSD report option provides the same calculations as the DFT Pore Size
report option and more. The NLDFT report compares two sample files. The models that can be
selected are restricted to only those models which have the same analysis temperature and
analysis gas as the sample file that is open. For instance, if the sample file was analyzed with N2
at 77degrees Kelvin, then only the N2 DFT models at 77degrees Kelvin will be available in the
Model drop-down list.
The model curve fit is shown in the lower right quadrant along with the adsorption isotherm. This
curve fit is updated each time the calculation parameters change (selection of isotherm data
points, choice of model, choice of regularization parameter).
A second sample file and second model is used to compute a more accurate pore size distribution
(PSD), which is shown in the upper left quadrant. Typically, the second sample file will have used
the same sample material as the first sample file yet will have used a different analysis gas and
temperature.
In general, the isotherm for this second sample will be different than the first sample. The
advanced DFT calculation takes the data from both sample files and combines all this data into a
more accurate calculation of the pore size distribution. More accurate means getting the pore
distribution at smaller pore sizes (a few Angstroms) as well as larger pore sizes (one thousand
Angstroms).
NLDFT Advanced PSD Report
TriStar II Plus Operator Manual
303-42800-01 (Rev M ) — Sep 2023
8 - 43

Micromeritics TRISTAR II PLUS Specifications

General

Brand	Micromeritics
Model	TRISTAR II PLUS
Category	Measuring Instruments
Language	English