Malvern Zetasizer Nano Series, Руководство пользователя

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.
I
A
: Residual scattering intensity of the analyte (i.e. the sample intensity –
solvent intensity).
.
I
T
: Toluene scattering intensity.
.
n
o
: Solvent refractive index.
.
n
T
: Toluene refractive index.
.
R
T
: Rayleigh ratio of toluene.
Rayleigh scattering
The scattering angle P
q
in the Rayleigh equation embodies the angular
dependence of the sample scattering intensity. The angular dependence arises
from constructive and destructive interference of light scattered from different
positions on the same particle , as shown below. This phenomenon is known as
Mie scattering , and it occurs when the particle is large enough to accommodate
multiple photon scattering.
However when the particles in solution are much smaller than the wavelength of
the incident light, multiple photon scattering will be avoided. Under these
conditions,
P
q
will reduce to 1 and the angular dependence of the scattering
intensity is lost. This type of scattering is known as Rayleigh scattering .
The Rayleigh equation will now be:
C H A P T E R 1 4
Z e t a s i z e r N a n o S e r i e s
P a g e 1 4 . 3
Destructive
Interference
Constructive
Interference
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