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SYSTEMATICS IN RYDBERG-STATE EXCITATIONS FOR BEAM-FOIL PROCESSES
B. Andresen, E. Veje
To cite this version:
B. Andresen, E. Veje. SYSTEMATICS IN RYDBERG-STATE EXCITATIONS FOR BEAM- FOIL PROCESSES. Journal de Physique Colloques, 1979, 40 (C1), pp.C1-261-C1-262.
�10.1051/jphyscol:1979155�. �jpa-00218435�
JOURNAL DE PHYSIQUE Colloque C1, suppliment au n O 2, Tome 40, fgvrier 1979, page C1-261
SYSTEMATICS I N RYDBERG-STATE EXCITATIONS FOR Bm-FOIL PRGCESSES
B. Andresen and E. V e j e
P h y s i c s L a b o r a t o r y 11, H.C. O r s t e d I n s t i t u t e , U n i v e r s i t e t s p a r k e n 5 , EK-2100 Copenhagen 8 Denmark
RBsumG. Nous avons mesurds d e s popul.atiocs r e l a t i v e s < . La p o e ~ l a t i o n r e l a t i v e
--
pour l a meme s e r i e d e Rydberg d e c r o i t p l u s r a p i d e m e n t que n,
comme o n l ' a a u s s i o b s e r v e d a n s l e s c o l l i s i o n s ion-atomes. Pour u m c e r t a i n e v a l e u r d e n l a p o p u l a t i o n r e l a t i v e augmente du niveaux s a p , d e c r o i t du p d e t e n c o r e augmente d@ d S g. C e t t e o b s e r v a t i o n e s t d i f f e r e n t e d e s c o l l i s i o n s ion-atomes.n e s d e v i a t i o n s c o n s i d e r a b l e s d e s p o p u l a t i o n s s t a t i s t i q u e s o n t e t 6 o b s e r v e s s pour l e s niveaux d e l a c o n f i g u r a t i o n 3 p Q NeI e t MgIII.
A b s t r a c t . We have measured r e l a t i v e l e v e l p o p u l a t i o n s . The r e l a t i v e l e v e l p p g u l a t i o n f o r terms o f t h e same Rydberg s e r i e s d e c r e a s e s somewhat f a s t e r t h a n n
,
a s a l s o o b s e r v e d i n ion-atom c o l l i s i o n s . The r e l a t i v e l e v e l p o p u l a t i o n f o r f i x e d n i n c r e a s e s from s t o p l e v e l s , d e c r e a s e s t o d l e v e l s , and showa n o t h e r i n c r e a s e from d t o g l e v e l s . T h i s i s d i f f e r e n t from ion-atom c o l l i s i o n s . L a r g e d e v i a t i o n s from s t a t i s t i c a l p o p u l a t i o n s were o b s e r v e d f o r t h e d i f f e r e n t l e v e l s o f t h e 3p c o n f i g u r a t i o n i n N e I and Mg111.
We have s t u d i e d l e v e l e x c i t a t i o n s i n neon and magnesium. The reslllts,
t o g e t h e r w i t h r e s u l t s on H , L i , Be, C , and Zn [ I ] , i n d i c a t e some s y s t e m a t i c a l t r e n d s c o n c e r n i n g beam-foil l e v e l p o p u l a t i o n s a s f u n c t i o n s o f t h e p r o j e c t i l e e n e r g y , t h e f o i l tilt a n g l e , and o f t h e f i n a l term quantum numbers.
I n most c a s e s i t i s o b s e r v e d , t h a t d i f f e r e n t l e v e l s o f t h e same v a r i e t y
( i . e . d i f f e r e n t l e v e l s w i t h t h e same c o r e c o n f i g u r a t i o n and o f t h e same c h a r g e s t a t e )
d i s p l a y t h e same r e l a t i v e v a r i a t i o n of photon y i e l d v e r s u s t h e p r o j e c t i l e e n e r g y . The o n l y known e x c e p t i o n s from t h i s
e m p i r i c a l r u l e a r e some MgII and ZnI l e v e l s . We want t o emphasize how
r e m a r k a b l e t h i s p r o p o r t i o n a l i t y i s , and recommend t h a t it be u s e d a s a t o o l f o r c h a r g e - s t a t e c l a s s i f i c a t i o n o f new s p e c t r a l l i n e s . One warning, however i s a p p r o p r i a t e : E x c i t a t i o n f u n c t i o n s f o r l e v e l s o f
d i f f e r e n t c h a r g e s t a t e s w i l l i n some c a s e s a p p e a r p r o p o r t i o n a l o v e r wide p r o j e c t i l e e n e r g y r a n g e s . T h i s i s f o r i n s t a n c e o b s e r v e d f o r MgI and MgII l e v e l s a t 200
-
900 keV.F i g . 1 shows t h e r e l a t i v e photon
I I I L I I I I I I I I I
0 200 LOO 600 'BOO 1000
EMERGENT BEAM ENERGY. keV
F i g . 1
-
R e l a t i v e photon y i e l d f o r a t r a n s i t i o n i n MgIII v e r s u s t h e p r o j e c t i l e energy and w i t h f o i l s t i l t e doO,
30' and 45O.y i e l d v e r s u s t h e p r o j e c t i l e e n e r g y f o r a t r a n s i t i o n i n MgIII w i t h f o i l s t i l t e d
oO,
30° a n d 45O. The photon y i e l d i s remarkably d e p e n d e n t o n t h e f o i l tilt a n g l e . The same h a s been s e e n and d i s c u s s e d f o r beam-foil e x c i t a t i o n o f c a r b o n ( t h e s e p r o c e e d i n g s ) .The r e l a t i v e l e v e l e x c i t a t i o n o f d i f f e r e n t l e v e l s w i t h i n t h e same term h a s been measured i n some c a s e s . We o b s e r v e a n a l m o s t s t a t i s t i c a l l e v e l p o p u l a t i o n
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:1979155
c
1-262 JOURNAL DE PHYSIQLEf o r l e v e l s which a r e w e l l d e s c r i b e d by LS c o u p l i n g , whereas l a r g e d e v i a t i o n s from s t a t i s t i c a l p o p u l a t i o n s a r e observed f o r t h e d i f f e r e n t l e v e l s o f t h e 3p c o n f i g u r a t - i o n i n NeI and MgIII.
The r e l a t i v e l e v e l p o p u l a t i o n f o r t e r m s o f t h e same Rydberg s e r i e s d e c r e a s e s somewhat f a s t e r t h a n n-3
,
see F i g . .2. For f u r t h e r examples ( H I L i , Be,C, and Zn ) s e e t h e s e p r o c e e d i n g s . The same b e h a v i o u r was found i n ion-atom
c o l l i s i o n s C21, and e x p l a i n e d q u a l i t a t i v e l y from t h e Rydberg s t a t e wave f u n c t i o n
n o r m a l i z a t i o n .
Mg - C FOIL 100 keV Mg 11
c
OW1 b 5 6 7 8
EFFECTIVE PWNlUH WUHBER. n*
F i g . 2
-
R e l a t i v e l e v e l p o p u l a t i o n s f o r t e r m s i n MgII v e r s u s t h e p r i n c i p a l quantum number.F i g . 3
-
R e l a t i v e l e v e l p o p u l a t i o n s f o r t e r m s i n MgII v e r s u s t h e o r b i t a l a n g u l a r momentum quantum number.i n p o p u l a t i o n f o r p l e v e l s . T h i s i s d i f f e r e n t from ion-atom c o l l i s i o n s , where t h e c r o s s s e c t i o n s peak f o r d l e v e l s a t low t o medium p r o j e c t i l e e n e r g i e s 131, and g r a d u a l l y s h i f t t o p and l a t e r t o s l e v e l s w i t h i n c r e a s i n g p r o j e c t i l e e n e r g y .
P a r t o f t h e ' measurements were c a r r i e d o u t at t h e I n s t i t u t e o f P h y s i c s , U n i v e r s i t y o f Arhus. EV wants t o thank t h e I n s t i t u t e f o r t h e g r e a t h o s p i t a l i t y h e e n j o y e d d u r i n g h i s s t a y . Also economic s u p p o r t from t h e Danish N a t u r a l R e s e a r c h S c i e n c e F o u n d a t i o n i s g r e a t l y a p p r e c i a t e d . The r e l a t i v e p o p u l a t i o n d a t a g i v e n
i n F i g . 2. a r e i n F i g . 3 r e p l o t t e d v e r s u s REFERENCES
t h e o r b i t a l a n g u l a r momentum quantum [ l ] See t h e s e p r o c e e d i n g s .
number o f t h e e x c i t e d l e v e l . A s i m i l a r 121 B. Andresen, K. J e n s e n , N.B. P e t e r s e n p i c t u r e a s t h a t s e e n i n F i g . 3 i s o b s e r v e d and E . Veje, Phys. Rev. A,
12,
1 4 6 9 f o r l e v e l s i n L i , Be, C , and Zn ( t h e s e ( 1 9 7 7 ) .p r o c e e d i n g s ) , namely t h a t t h e r e l a t i v e 131 B. Andresen and E. V e j e , Phys. Rev. A , l e v e l e x c i t a t i o n f o r l e v e l s o f t h e same
-
1 6 , 1980 ( 1 9 7 7 ) .p r i n c i p a l quantum number i n c r e a s e s w i t h t h e o r b i t a l a n g u l a r momentum quantum number e x c e p t f o r a superimposed p e a k i n g
