Chemistry Reference
In-Depth Information
Ewald sphere
Limiting sphere
P (
hkl
)
P
¢
H
hkl
b*
s
/
l
2
q
O
C
s
0
/
l
a*
1/
l
2/
l
FIGURE 1.14 Limiting sphere for the powder diffraction.
in Figure 1.15. The end of s/l vector forms a circle on the Ewald sphere passing
through the reciprocal lattice point P(hkl ), P
0
(hkl ), and all equivalent reciprocal
lattice points. The diffracted beams form a conewith the incident beamon the rotation
axis. This cone is referred to as diffraction cone. The 2u angle can take values from0 to
Diffraction vector cone
Diffraction cone
Ewald sphere
P (
hkl
)
s
/
l
H
hkl
X-ray
2
2
q
C
O
s
0
/
l
H
hkl
s
/
l
P
¢
(
hkl
)
FIGURE 1.15 Diffraction cone and diffraction vector cone illustrated on the Ewald sphere.
