ESR STUDIES ON ARSENIC-ASSOCIATED CENTERS IN OXIDE GLASSES PRODUCED BY GAMMA-IRRADIATION

HAL Id: jpa-00222461

https://hal.archives-ouvertes.fr/jpa-00222461

Submitted on 1 Jan 1982

HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers.

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

ESR STUDIES ON ARSENIC-ASSOCIATED CENTERS IN OXIDE GLASSES PRODUCED BY

GAMMA-IRRADIATION

H. Imagawa, H. Hosono, H. Kawazoe

To cite this version:

H. Imagawa, H. Hosono, H. Kawazoe. ESR STUDIES ON ARSENIC-ASSOCIATED CENTERS IN

OXIDE GLASSES PRODUCED BY GAMMA-IRRADIATION. Journal de Physique Colloques, 1982,

43 (C9), pp.C9-169-C9-172. �10.1051/jphyscol:1982932�. �jpa-00222461�

JOURNAL DE PHYSIQUE

CoZZoque C9, suppZkment au 12'12, Tome

dkcembre 1982 page

ESR STUDIES ON ARSENIC-ASSOCIATED CENTERS I N O X I D E GLASSES PRODUCED BY GAMMA-IRRADIATION

'Toshiba Research and DeveZopment Center, Toshiba Corporation, Komukai-Toshiba-cho, i w a s a k i 210, Jopan

" " ~ e p a r t m e n t of Inorganic Materials, Nagoya I n s t i t u t e of TechnoZogy, Gokiso, Showa-ku, Nagoya 466, Japan

* * * Department o f Industria2 Chemistry, Faculty o f Technology, Tokyo Metropo Zitan University , Fukasma, Setagaya-ku, Tokyo 158, Japan

Rbsum6.- Deux s o r t e s de nouveaux c e n t r e s a s s o c i b s

As dans l e v e r r e 16Na 0,11Ca0,73Si02:0,1As0 , i r r a d i G s aux

o n t & t E i d e n t i - f i 6 s p a r R ~ E . Le q u a r t e t h y p e r f i g , p r e s q u e i s o t r o p p r o d u i t p a r l e noyau 7 5 ~ s (1=3/2,A.N.=100%) q u i a p p a r a i t dans l e v e r r e oxydb

( s i g n a l 0 ) a b t b a s s i g n 6

un c e n t r e l i b

un piPge

b l e c t r o n s p r o v e n a n t de l ' i o n p r g c u r s e u r AS^+ . Le q u a r t e t hf de s y m b t r i e a x i a l e observb dans l e v e r r e r 6 d u i t a b t b a t t r i b u 6

un c e n t r e

~ i b g e a g e d e t r o u de l ' i o n AS^+. Les p a r a m c t r e s RPE o n t 6 t d bva- l u 6 s en u t i l i s a n t l a t e c h n i q u e de s i m u l a t i o n de l a forme d e s r a i e s . Les c o e f f i c i e n t s LCAO o n t b t 6 d 6 r i v b s 3 p a r t i r de c e s paramPtres. Les modPles s t r u c t u r a u x q u i en d 6 c o u l e n t s o n t c e n t r 6 s

p i s g e

G l e c t r o n s (ASS+)- de c o o r d i n a t i o n t g t r a s d r i q u e , 1 1 6 1 e c t r o n pibg6 6 t a n t s u r une o r b i t a l e a n t i l i a n t e As-0

c e n t r e

t r o u pi6gb (ils3+)+ en c o o r d i n e n c e t r i g o n a l e p y r a m i d a l e , l e t r o u occupant une o r b i t a l e non l i a n t e

s p 3 h y b r i d b e .

A b s t r a c t . - Two k i n d s of new A s - a s s o c i a t e d c e n t e r s i n T - i r r a d i a t e d

~6Na20.11Ca0-73Si~2:0.1AsOx g l a s s were i d e n t i f i e d by ESR e x p e r i - ments. The n e a r l y i s o t r o p i c h y p e r f i n e q u a r t e t produced by a 7 5 ~ s n u c l e u s ( I = 3 / 2 , N.A.=100%) a p p e a r i n g i n o x i d i z e d g l a s s ( 0 - s i g n a l ) was a s s i g n e d t o an e l e c t r o n - t r a p c e n t e r o r i g i n a t i n g from a p r e - c u r s o r ASS+ i o n . The hf q u a r t e t of a x i a l symmetry observed i n reduced g l a s s was a t t r i b u t e d t o a h o l e - t r a p c e n t e r o r i g i n a t i n g from an AS^+ i o n . ESR p a r a m e t e r s were e v a l u a t e d by use o f l i n e s h a p e , s i m u l a t i o n t e c h n i q u e . LCAO c o e f f i c i e n t s were d e r i v e d from t h e p a r a m e t e r s . The s t r u c t u r e models f o r t h e c e n t e r s were proposed on t h e b a s i s o f t h e c o e f f i c i e n t s : t h e e l e c t r o n - t r a p c e n t e r ,

AS^+) -, h a s a t e t r a h e d r a l c o o r d i n a t i o n , t h e t r a p p e d e l e c t r o n l o c a t i n g on an As-0 a n t i - b o n d i n g

t h e h o l e - t r a p c e n t e r ,

AS^+)+, h a s a t r i g o n a l l y pyramidal c o o r d i n a t i o n , t h e h o l e occupy- i n g a non-bonding

s p 3 h y b r i d i z e d o r b i t a l .

1. I n t r o d u c t i o n . - R a d i a t i o n - i n d u c e d d e f e c t s l o c a l i z e d i n a network- forming polyhedron i n o x i d e g l a s s e s have been e x t e n s i v e l y i n v e s t i g a t e d s i n c e Weeks' work [ l ] on S i E l - c e n t e r i n S i 0 2 g l a s s . The c e n t e r s analogous t o S i

were d e t e c t e d f o r B-

Ge- [31 and A l - [ 4 1 oxygen p o l y h e d r a . R e c e n t l y , T a y l o r e t a l . [51 o b s e r v e d a paramagnetic c e n t e r a s s o c i a t e d w i t h

i n electron-bombarded

and As2Se3 g l a s s e s . The semi-occupied m o l e c u l a r o r b i t a l (SOMO) i n t h i s c e n t e r was found t o be a l m o s t composed o f

4p a t o m i c o r b i t a l .

s i m i l a r p a r a m a g n e t i c d e f e c t was r e p o r t e d i n r - i r r a d i a t e d As203 g l a s s by Pontuschka and T a y l o r [ 6 ] . I n t h i s p a p e r , we r e p o r t two k i n d s of paramagnetic d e f e c t s i n which A s 4 s c o n t r i b u t e t o t h e SOMO t o a l a r g e e x t e n t .

Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1982932

JOURNAL

PHYSIQUE

I I

r D

1000 2000 3000 4000 5000 MAGNETIC FIELD (GI

Fig.liY-induced ESR s i g n a l i n ox- i d i z e d g l a s s ; 0 - s i g n a l . ( a ) Ex- p e r i m e n t a l c u r v e . I n t e n s e ab-

s o r p t i o n s i n t h e c e n t r a l p a r t i s due t o oxygen h o l e c e n t e r s i n t h e g l a s s m a t r i x

s h a r p a b s o r p t i o n n e a r 1500G i s due t o ~ e 3 + i m p u r i t y . ( b ) Calc- u l a t e d c u r v e . Gaussian d i s t r i - b u t i o n was assumed f a r

1 I I I I

1000 2000 3000 4000 50G0 MAGNETIC FIELD (G)

F i g . 2 Y-induced ESR s i g n a l i n r e - duced g l a s s ; R - s i g n a l . ( a ) Ex- p e r i m e n t a l c u r v e .

t r a c e o f

s i g n a l i s s e e n n e a r 1000 and 5000

I n t h e c e n t r a l p a r t

s p e c t r a o f AS^+ 1121 and t h e ox- gen h o l e c e n t e r i n t h e m a t r i x a r e s u p e r p o s i n g . ( b ) C a l c u l a t e d c u r v e . Gaussian d i s t r i b u t i o n was assumed f o r

2. Experimental.- Sample g l a s s e s o f nominal composition 16Na20.llCaO- 73SiO2 i n c l u d i n g 0.1 A s 2 0 ~ ( i n mole%) were p r e p a r e d from h i g h l y p u r e chemicals under o x i d i z i n g o r r e d u c i n g c o n d i t i o n . I n o r d e r t o p r e p a r e t h e reduced g l a s s , a h a l f p o r t i o n o f Na20 and CaO were s u p p l i e d a s o x a l a t e s which a c t a s r e d u c i n g r e a g e n t s and a n o t h e r h a l v e s were p r o v i d e d w i t h t h e c a r b o n a t e s . The b a t c h was m e l t e d i n an alumina c r u c i b l e w i t h a f u s e d q u a r t z c o v e r t o p r e s e r v e t h e r e d u c i n g a c t i o n d u r i n g t h e f u s i o n p r o c e s s . The o x i d i z e d g l a s s was p r e p a r e d by p l a c i n g a c r u c i b l e i n a m u f f l e t h r o u g h which oxygen g a s was flowed and by blowing oxy e n gas t o t h e m e l t f o r 30 min a t 1300°C. C o n c e n t r a t i o n s o f lis3+ and

were determined by wet chemical a n a l y s e s .

was found t h a t ~ 9 0 % of A s was p r e s e n t a s AS^+ i n t h e reduced g l a s s and = l o % ^{i n}

t h e o x i d i z e d g l a s s . About h a l f amount o f

added t o t h e b a t c h was v a p o r i z e d away p e r h a p s due t o f a s t v o l a t i l i z a t i o n of A s d u r i n g g l a s s m e l t i n g p r o c e s s i n r e d u c i n g atmosphere. The m e l t s were d i r e c t l y drawn i n t o r o d s 4mm i n d i a m e t e r and 300mm l o n g f o r ESR measurements.

The sample r o d s were i r r a d i a t e d by $-rays from a 6 0 ~ o s o u r c e a t a r a t e of 5 . 8 x 1 0 5 ~ / h f o r 2 h r s a t 77K. F i r s t d e r i v a t i v e c u r v e s of

band ESR s p e c t r a were measured w i t h a JEOL model PE-3X s p e c t r o m e t e r a t 77K w i t h o u t i n t e r v e n i n g warm-up a f t e r t h e i r r a d i a t i o n . Applied magnetic f i e l d s and resonance microwave frequency were c a l i b r a t e d w i t h a p r o t o n

f i e l d marker and a c a v i t y wavemeter, r e s p e c t i v e l y .

3. R e s u l t s .

3 . 1 ESR s i g n a l f o r o x i d i z e d g l a s s ; 0 - s i g n a l . - F i g u r e 1 shows an ESR spectrum f o r t h e o x i d i z e d g l a s s . The s i g n a l r a n i n g from 1500 t o 5000G i s r e g a r d e d a s a q u a r t e t o f h f peaks d u e t o a 7 z A s n u c l e u s (7=3/2, N.A.=100%). The a n a l y s i s o f 0 - s i g n a l was made on t h e b a s i s o f t h e f o l l o w i n g s p i n H a m i l t o n i a n ,

x =

+ AX-.%. (1)

The ESR p a r a m e t e r s were e s t i m a t e d from t h e B r e i t - R a b i s o l u t i o n t o e q . (1) and g i v e n a s

- 3 h g ( l + ~ ) + h v ( 9 ( 1 + ~ )

+ 1 6 (1-K) 2)1/2

4

( 2 )

2h

hJ+2A

g

- ^{( 3 )}

PH+ ^{2hV +A'}

where K means t h e r a t i o o f

and H+ d e n o t e t h e z e r o c r o s s i n g f i e l d o f t h e l o w e s t and h i g h e s t h f a b s o r p t i o n s , r e s p e c t i v e l y ) . The l i n e s h a p e s i m u l a t i o n was a c h i e v e d by i n t r o d u c i n g a d i s t r i b u t i o n i n

which r e f l e c t s t h e s t r u c t u r a l randomness o f t h e c e n t e r r e s p o n s i b l e f o r 0 - s l g n a l , and a l s o t a k i n g e x p l i c i t l y t r a n s i t i o n p r o b a b i l i t y f o r e a c h a b s o r p t i o n i n t o c o n s i d e r a t i o n . The e v a l u a t e d p a r a m e t e r s a r e l i s t e d i n Table 1.

3.2 ESR s i g n a l f o r reduced g l a s s ; R - s i g n a l . - F i g u r e 2 e x h i b i t s t h e

s p e c t r u m f o r Y - i r r a d i a t e d g l a s s f u s e d under r e d u c i n g c o n d i t i i o n .

t r a c e o f 0 - s i g n a l i s o v e r l a p p i n g w i t h a n o t h e r t y p e o f h f q u a r t e t . The q u a r t e t i s r e f e r r e d t o a s R - s i g n a l . The l i n e shape o f R - s i g n a l i s r a t h e r a n i s o t r o p i c . T h e r e f o r e , t h e a n a l y s i s o f t h e s p e c t r u m was

c a r r i e d o u t by using_Hamiltonian

x = p.s-5-xi + I-A-a. ( 4 ) Here, we assume t h a t < i s isotropic a n d z h a s a x i a l - s y m m e t r i c c h a r a c - t e r . The ESR p a r a m e t e r s were e x t r a c t e d employing t h e second o r d e r p e r t u r b a t i o n s o l u t i o n

t h r o u g h t h e computer s i m u l a t i o n o f t h e l i n e s h a p e ( ~ i g . 2 ) . They a r e summarized i n T a b l e 1. The d i s t r i b u t i o n o f

was n e c e s s a r y i n t h e s i m u l a t i o n t o f i t t h e l i n e shape c l o s e l y . T h i s d i s t r i b u t i o n i s t h e m a n i f e s t a t i o n o f t h e v a r i a t i o n i n bond l e n g t h s and bond a n g l e s . From s i m p l e m o l e c u l a r o r b i t a l t h e o r y [ l o ] , t h e v a r i a - t i o n s i n t h e a n g l e , Q , between t h e d a n g l i n g bond, o114s) + P14p) , and t h e d i r e c t i o n o f As-0 bonding i s g i v e n by

2 1/2

case= - [ d 2 / 3 8 I .

The h a l f - w i d t h i n t h e d i s t r i b u t i o n i s t r a n s f o r m e d t o t h e f l u c t u a t i o n o f 0 . The f i r s t o r d e r a p p r o x i m a t i o n i s

By means o f e q . ( 5 ) , a e w a s e y a l u a t e d t o h e ~ 0 . 7

T h i s v a l u e i s comparable t o t h a t f o r S i E c e n t e r i n S i 0 2 g l a s s .

4. D i s c u s s i o n . - According t o t h e r e s u l t s o f Raman s c a t t e r i n g s t u d y [ l l ] on a l k a l l s i l i c a t e g l a s s e s c o n t a i n i n g s m a l l amount o f

p e n t a v a l e n t and t r i v a l e n t

t a k e t e t r a h e d r a l ( a n a 1 o g o u s t o P04) and t r i g o n a l l y - pyramidal c o o r d i n a t i o n , r e s p e c t i v e l y .

The proposed s t r u c t u r a l models f o r 0- and R-signal a r e i l l u s t - r a t e d i n F i g . 3 .

0-

and R - s i g n a l s a r e a s s i g n e d t o

and

r a d i c a l s , r e s p e c t i v e l y by c o n s i d e r i n g t h e above-mention and t h e e v a ? u a t e d

c o e f f i c i e n t s o f SOMO. The former i s induced when ASS+ t r a p p s an e l e c t r o n and t h e l a t t e r i s produced by h o l e - c a p t u r i n g on

T h i s a s s i g n m e n t i s made by comparing t h e p a r a m e t e r s w i t h t h o s e r e p o r t e d f o r v a r i o u s r a d i c a l s i n t h e l i t e r a t u r e s ( T a b 1 e 2 ) .

The ~ ~ 0 c e n t e r f i r s t l y i d e n t i f i e d i n t h i s work ~ 2 - i s a n a l o g o u s

t o t h e well-known S i

c e n t e r b u t an a n a l o g u e f o r t h e

h a s

n e v e r d e t e c t e d i n g l a s s . The s t r u c t u r a l r e l a x a t i o n o f b o t h t h e c e n t e r s

upon a n n e a l i n g a f t e r r f - i r r a d i a t i o n w i l l be d i s c u s s e d i n o u r succeed-

i n g p a p e r El21 .

JOURNAL DE PHYSIQUE

T a b l e 1. T h e

a n d "R" s i g n a l s

S i g n a l 0 R

4 p - c h a r a c t e r * *

6 6 %

* the s t a n d a r d d e v i a t i o n for t h e d i s t r i b u t i o n of A.

0

** c a n p a r e d w i t h A

34196 f o r 4 s

a n d

91G for 4 p orbital of the

o+o ^free

^atam.

0

T a b l e 2 S p i n d e n s i t i e s of A s c e n t e r s i n l i t e r a t u r e s

C e n t e r

R - SIGNAL 4 s ( % ) 4 p ( % ) R e f .

0

- SIGNAL

'AS0;- i n Na2HAs04.7H,0 1 8 . 1 59.3 [141

AS^+ ^{) - (} AS^+ ⁾

in CXo3 ( c a l c i t e ) 23.8 6 8 . 1 ~ 1 5 1

4 in m 2 A s 0 4 31.7 41.8 [16]

* A s

(OH) in H3As04-H2S04 40.2 -

F i g . 3 . F o r m a t i o n of p a r a r m g n e t i c [I71

As

c e n t e r s upon y - i r r a d i a t i o n a t 77K.

i n H3As04-WCN 32.2 - [I71

References.

111 W e e k s R. A . ,

A p p l . P h y s . , z ( 1 9 5 6 ) 1 3 7 6 . [ 2 1 G r i s c o m

L ,

Chem. P h y s . , g ( 1 9 7 1 ) 1 1 1 3 .

[ 3 1 W e e k s

A. a n d P u r c e l l T . ,

C h e m . P h y s . , g ( 1 9 6 5 1 4 8 3 . 1 4 1 B r o w e r

P h y s . R e v . , B 2 0 ( 1 9 7 9 ) 1 7 9 9 .

[ 5 1 T a y l o r P . C . , S t r o m U. a n d i s h o p S . G . , P h y s . R e v . , B 1 8 ( 1 9 7 8 ) 5 1 1 . [ 6 ] P o n t u s c h k a

M. a n d T a y l o r

C . , S o l i d S t a t e Commun.,=(1981)

5 7 3 .

[ 7 ] A l b i n a k M.

a n d T u r n e r

H . , U. S . P a t e n t 3 , 3 4 5 , 1 9 0 ( 1 9 6 7 ) . 1 8 1 T a y l o r P . C . , B a u g h e r

F. a n d K r i z H. M., Chem. R e v . , c ( 1 9 7 5 )

2 0 3 .

[ 9 1 S c h r e u r s

H.,J. C h e m . P h y s . , e ( 1 9 6 7 ) 8 1 8 . [ l o ] C o u l s o n C. A . , " V a l e n c e " ( O x f o r d U n i v . , L o n d o n , 1 9 6 1 ) . 1 1 1 1 V e r w e i j H,

N o n - C r y s t . S o l i d s . , 38

2 ( 1 9 8 0 ) 8 8 5 . 1 1 2 1 I m a g a w a H, H o s o n o H . , a n d K a w a z o e

J . C h e m . P h y s . ,

t o be p u b l i s h e d .

1 1 3 1 W e r t z J . E . , a n d B o l t o n J . R . , " E l e c t r o n S p i n R e s o n a n c e E l e m e n t a r y T h e o r y a n d P r a c t i c a l A p p l i c a t i o n s " , M c G r h w - H i l l ( l 9 7 2 ) .

[ 1 4 ] L i n W.C., a n d M c D o w e l l

[ 1 5 ] S e r w a y R . A . , a n d M a r s h a l l S . A . , J . C h e m . P h y s . , s ( 1 9 6 6 ) 2 3 0 9 . [ 1 6 ] H a m p t o n M., H e r r i n g F . G . , L i n W.C., a n d M c D o w e l l C . A . ,

Mo1.Phy.s. , 1 0 ( 1 9 6 6 ) 5 6 5 .

[ 1 7 ] G i n n s I . S . T ~ i s h r a S . P . , a n d S y m m o n s M.C.R., J . C h e m . S o c . ,

( 1 9 7 3 ) 2 5 0 9 .