. f , , ,
f = E/E . (2.38)
(I~E2), .
. 2.15. .
, , . , , [2]:
× × , (2.39)
R - ; 2q - ; I I0 - .
, , . , . Z , - ri, , , [2]:
E = , (2.40)
sri - , ,
i- .
() , E . . f . f , , , - , . f f [2]. , sinq/l.
, , , , .. .
, 2 (.2.15). , x, y, z. S0 S , :
(R [ S - S0 ]) = d (2.41)
:
d = j (2.42)
d (2.41) (S - S0) (2.28) :
j=2p(HR)=2p(Hx+Ky+Lz) (2.43)
:
F = fo eij (2.44)
2 , j ,
F = eij (2.45)
f0 , , o
|
|
F= j e2pi (Hx+Ky+Lz) , (2.46)
x, y, z - ; fj - ; H, K, L - , , , , ; j - .
F . , , . H, K, L . , , .
. eix = cos x + i sin x, :
F = j cosjj + i j sinjj , (2.47)
jj = 2p(Hxj + Kyj +Lzj).
.
1. , . - , :
FHKL = [1+epi(H+K+L)]×f (2.48)
.
FHKL= [1+cos p(H+K+L) + i sin p(H+K+L)]×f. (2.49)
H, K, L - , sin p(H+K+L) , :
FHKL = [1+cos p(H+K+L)]×f (2.50)
, .. H+K+L=2n, FHKL = 2f.
, .. H+K+L¹2n, FHKL=0.
, , , , 100, 111, 210, 221, 311, 320, 410 ..
, , .. , .
2. , , . FHKL,
FHKL= [1+epi(H+K)+epi(H+L)+epi(K+L)]×f.
, . , ( p) 0. :
FHKL = [1+cosp(H+K)+cosp(H+L)+cosp(K+L)]×f. (2.51)
(2.51) H, K, L FHKL=4f; H, K, L FHKL=4f H, K, L ( ) FHKL=0.
(2.51) , , (0-), , , : 100, 110, 210, 211, 221, 310 ..
F , , . , . , , .
|
|
3. . (000, 1/2, 1/2, 1/2).
FHKL = fA×1 + fB×epi(H+K+L) = fA + fBcosp(H+K+L). (2.52)
(2.52) :
H+K+L , F= fA+fB
H+K+L , F =fA - fB
, , . , A B (fAfB), , (, H+K+L ).
fA fB , , .
, , .