29
0
0.1
0.2
1 10 100
Size Distribution
Relative
Frequency
Radius [nm]
1000
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
1 10 100
Relative
Frequency
Radius [nm]
1000
Size distribution fit gives the blue trace, while cumulant
analysis shows the average particle size in dashed red.
For a monodisperse system (top), the cumulant radius
is centred within the intensity distribution curve. For a
polydisperse system (bottom), it lands between the two
size populations.
Peaks may exhibit widening, or there may be many peaks
present in the system.The standard deviation around the
mean r
H
is used to determine the polydispersity index, or
PDI, which will tell you about your sample quality. See
the full discussion below in Section 4.
