Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.chem.msu.ru/rus/cryst/srschool/pdf/menushenkov.pdf Дата изменения: Tue Nov 22 12:51:00 2005 Дата индексирования: Sat Dec 22 15:09:46 2007 Кодировка:

(XAFS ­ )
XAFS ­ X-ray A b so rption Fine Structure

E XAFS -External X-ray Absorption Fine Structure XANE S - X-ray Near Edge S tructure -





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80 : Her t z G. //Z. Physik , v. 3, 1920, p. 19. Fr icke H. //P hy s.Rev. v. 16, 1920, p. 202. Lindh A.E. //Z. Physik , v. 6, 1920, p. 303; v. 31, 1925, p. 210. Co st er D. //Z. P hysik , v. 25, 1924, p. 83. : de L. Kronig R. // Z. P hysik , v. 70, 1931, p. 317. ­ : . de L. Kronig R. // Z. P hysik , v. 70, 1932, p. 468. ­

XA F S: P et er son H. //Z. Physik , v. 76 , 1932, p. 768; v. 80, 1933, p. 528, v. 98, 1936, p. 969. .. // .11, c. 60 , . 19 , 1941, . 413. Sa wa da M. // Rep . Sci. W o r k s Osak a Un iv . v .7 , 1959, p. 1. . . // . , . . . 2 5 , 1961, . 977; . 27, 1963, . 392. .. // . , . . . 2 5 , 1961, . 957; .2 7, 1963, . 364; . 38, 1964, . 50 0 - Say er s D.E., St er n E.A., Lyt le W .F.// P hy s.Rev .Lett v.27, 1971, p. 1024.

XAF S . : 1 - EXAFS- -3 ( .. .) . - - : EXAF S- XANE S ­ : . . , .. , .. . : .. ., : - .. , .. , - . . . ­ .. , .. ­ .. .

: 1. .. , .. , .. . // EXAFS- . , , 1988, 306 . 2. . ., .. , .. , .. //, .1 49 , 1986, . 275. 3. .. , .. , .. , . // , . 32, 2001, . 6 , . 1299. 4. J.J. Rehr , R.C. Alber s / / Rev. Mo d. P hys., v. 72 , 2000, p. 621.

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: 1. FEFF 8. 12 - J.J. Reh r, A .A n ku d ino v et al. 2. EDA ­ EXA FS d ata an alys is ­ . . 3. IFEF FIT: in teractiv e XA FS an alys is an d FEFF fittin g ­ M .Newv ille 4. VIP ER ­ Vis ual process ing in EXA FS res earch es fo r W in do ws ­ .. : h ttp ://www.d es y .d e/~klmn /v ip er.html

EXAF S- . 1. " "
2. ­ (Fluo res c en ce ) FEX AFS 3. ­ (S u r fac e) S E XAF S : - , , , 4. EX AFS- ( X- ray Ex cited Opti cal Lumin esc en ce ­ XE OL ) 5. (C irc ula r Ma gneti c X -r ay Dih roism ­ C MX D) 6. (Di ffr a ction Anom alous F ine Structu re ­ D AFS)

0.8

E X AFS-
7 6 5 3 2 1

µ

µ0

EX AFS : µ = ln( I t / I 0 )
k= 2 me ( E - E 0 ) /

0.6

µ, . .

0.4 0.2 0.0

-0 .2

µback
E
1 340 0
0

gr

(k ) =
8 9 10 4

µ (k ) - µ 0 (k ) µ 0 (k ) - µ backgr ( k)
( k) = -


a
n

E, 3 (e ra )2 fa ( k, ) sin( 2 kra + 2 1( k ) + a (k , )) kra2

1 3600

13 800

140 00

EXAF S - :

(k ) = -



n

1 g (r ) f ( k, ) n 2 sin(2kr + 21 (k) + n( k, )) dr kn r
Nn 2 f ( k , ) sin( 2 kR n + 2 1 (k ) + n ( k , )) e kR n n
2 - 2 n k 2

(k ) = -

11 13 12

g n (r ) = N

n



n ' ( r) e-

2

E n ' / kT



e

-E n ' / kT

3


µ0
0. 8 0. 6
µ, . .

E X AFS- (k)

µ

µ

0

0. 4 0. 2 0. 0

-0. 2

µ

ba ckgr

E
1340 0

0

136 00

138 00

140 00

E,

­ :

E X AFS- (k) k-

: E0 , N R, Rn, 2

4


L3-Pb EXAF S- Ba PbO
0 1 4 8

3
5. 0 0. 0

k, е-1

12

16

20

.

(k)*k 2

0

I

5. 00. 1 5. 0

-1

]2k *)k ( [T FB

a)
3 2

0. 0

5. 0-

II
4. 0

FT[ (k)* k2]

1 0 -1 -2 -3 0

0. 0

I
2

II

III
4 6

b)
8
02 61 21
1 -е

I II
,k
8 4

4. 0-

r, е



(FEFF)

5


EXAFS- L3-Re ReO3( - )



2 = s2 + d

2 /T

d2 = /(2µ) · (1 + e-

)/(1- e-

/T

)

= /kB ­

C3i, C4i, C5i, C6i ­ , / .

- BaBiO Bi-O T < 90K. . . . A. Menushenkov et al. , P hysica 277, pp. 257-263, 1997

3

La1. 85Sr

0.15

CuO4

Cu-O CuO2 A .Lan zara et al. Ph ys ica C 29 6, 1 99 8, p p . 7-12

6


Ba1-xKxBiO

3

YB a2Cu 3O

7-y

Nd 2-xCexCu O

0.8
4-y

µ

µ0

EX AFS : µ = ln( I t / I 0 )
k=
2 me ( E - E 0 ) /

0.6

µ, . .

0.4 0.2 0.0

-0 .2

µback E
1 340 0
0

gr

µ (k ) - µ 0 (k ) (k ) = µ 0 ( k ) - µ backgr ( k)
( k) = -

1 3600


a
n

3(e ra )2
kra2



13 800 E,

140 00

fa ( k, ) sin(2kra + 2 1( k ) + a (k , ))

EXAF S - :

(k ) = -


n

1 f ( k, ) kn



gn (r ) sin( 2kr + 21 (k ) + n ( k , )) dr r2
2 - 2 n k 2

(k ) = -

Nn 2 f ( k , ) sin( 2 kR n + 2 1 (k ) + n ( k , )) e kR n n

g n (r ) = N

n



n ' ( r) e-

2

E n ' / kT



e

-E n ' / kT

E X AFS- (k) r-

(k) r- U(r)

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BaBiO3
EXAF S Bi-O


BaBiO
: BiO6 - Bi6sO2p *- ; BiL 2O6 - B i6sO2p *- .

3

2- : : BiO 6 --- Bi L2O
6

BaPbO3 :
:

Ba0.6 K0.4BiO3
, BiO6 BiL2O6 ( Ba BiO3) , BiL2O6 BiL2O6 -- ( BaP bO3)

PbL2O6


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Zn O6


:

, . 1(k) 2(k) 2 (M2>M1), D1 D2

1

F 0. 95% - 2(k) , D1/D2> F 0. 95% . F 0. 95% .

EXA F S- Al- Fe- Cu

ZrO

2

9


ZrN

XA NES


Muff in- t in

Sm Sm 0.67Y0.33S

10


EXAFS

XA FS -
(10-15 ) ,

11