An electron paramagnetic resonance study of the ethylammonium-, methylammonium-, and
acetamidinium-tetrachlorocuprates
by Paul Henry Amundson
A thesis submitted to the Graduate Faculty in partial fulfillment of the requirements for the degree of
MASTER OF SCIENCE in Physics
Montana State University
© Copyright by Paul Henry Amundson (1968)
Abstract:
A K-band electron paramagnetic resonance spectrometer was construc-ted in order to determine the
high and low field g-values, line shapes, and line widths for the spectra of divalent copper in
ethylammonium-tet-rachlorocuprate and methylammonium-tetrachlorocuprate. The g-tensors were
determined to be gxx = 2.053, gyy = 2.067, and gzz = 2.261 for ethyl-ammonium-tetrachlorocuprate
and gxx =2.054, gyy = 2.067, and gzz = 2.271 for methylammonium-tetrachlorocuprate. An exchange
frequency of 20.39 GHz for ethylammonium-tetrachlorocuprate and 17.48 GHz for
methylammonium-tetrachlorocuprate was computed. Data was also taken on
acetamidinium-tetrachlorocuprate to confirm earlier findings. AN ELECTRON. PARAMAGNETIC RESONANCE STUDY OF THE ETHYLAMMONIUM«
METHYLAIffiONIUM“ ? AND AGETAffiDINIUM-=TETRACHLOROCUPRATES
by
PAUL HENRY AMUNDSON
A t h e s i s s u b m itte d t o t h e G r a d u a te F a c u l t y i n p a r t i a l
- f u l f i l l m e n t o f t h e r e q u i r e m e n t s f o r t h e d e g re e
MASTER OF SCIENCE
in
P h y s ic s
A p p ro v e d :
G r a d u a te D ean
i/
MONTANA STATE UNIVERSITY
B ozem an, M o n ta n a ■
D ecem ber,- 1968
iii
A c k n o w le d g e m e n ts
■
The a u th o r - g r a t e f u l l y a c k n o w le d g e s t h e f i n a n c i a l s u p p o r t o f M ontana
S t a t e U n i v e r s i t y ( 1966 - 67 ) , o f t h e N a v a l W eapons C e n te r ( 1 9 6 7 - 6 8 ) , and o f
t h e N a t i o n a l S c ie n c e F o u n d a tio n ( Summer, 1 9 6 8 ) .'
-
He i s e x tr e m e l y g r a t e f u l t o P r o f e s s o r J o h n S . D ru m h e lle r , w hose a d ­
v i c e an d e n c o u ra g e m e n t w e re i n s t r u m e n t a l i n t h e a c c o m p lis h m e n t o f th e
w o rk .
The a u t h o r a l s o w is h e s t o t h a n k F . J . B la n k e n h u rg f o r t h e d e s ig n
a n d c o n s t r u c t i o n o f t h e m o d u la tio n o s c i l l a t i o n a m p l i f i e r and P r o f e s s o r
K. E m erson f o r g ro w in g t h e c r y s t a l s s t u d i e d .
iv
}
T a b le o f C o n te n ts
C h a p te r
Page
'
A b s tra c t
'
I.
In tro d u c tio n
II.
EPR o f C o p p e r C om plexes
III.
E x p e r im e n ta l R e s u l t s
IV .
The S p e c tr o m e t e r
The S p e c tr o m e t e r
O p e r a ti o n o f t h e S p e c tr o m e t e r
A p p e n d ix
L i t e r a t u r e C ite d
'
'
v ii
I
5
-.
9
1
- 17
26
• 31
3U
V
L i s t o f T a b le s
T a b le
' P age
I.
E x p e r im e n t a l R e s u l t s
II.
G-v a lu e s
II.
'
9
il^
G a u s s ia n and L o r e n t z i a n T h e o r e t i c a l D a ta P o i n t s
t•
33
vi
L i s t o f F ig u re s
F ig u re
P age
I.
E n e rg y L e v e l D ig ram f o r D i v a l e n t , C o p p e r
h
2.
D i s t o r t e d O c t a h e d r a l S ym m etry
7
3 .a ,b
C r y s t a l S t r u c t u r e s o f EATCC, MTCCj an d ACTCC
8
h.
EATCC E x p e r im e n t a l and T h e o r e t i c a l C u rv e s (lo w f i e l d )
10 .
5.
EATCC E x p e r im e n t a l an d T h e o r e t i c a l C u rv e s ( h i g h f i e l d )
11
6.
MATCC E x p e r im e n ta l an d T h e o r e t i c a l C u rv e s ( lo w f i e l d )
12
7.
MATCC E x p e r im e n ta l and T h e o r e t i c a l C u rv e s ( h i g h f i e l d )
13
8.
ACTCC R e p r e s e n t a t i v e E x p e r im e n t a l C urve
9.
B lo c k D ia g ra m o f t h e S p e c tr o m e t e r
18
10.
C i r c u i t D ia g ra m f o r 125 KHz A m p l i f i e r
20
11.
C i r c u i t D ia g ra m f o r 125 KHz O s c i l l a t o r - A m p l i f i e r
21
12 .
V a r i a b l e T e m p e r a tu r e C a v ity M ount
23
13.
2U.7. GHz M icrow ave C a v ity
2k'
lit.
K l y s t r o n Mode w i t h C a v i ty R e so n a n c e
27
15.
NMR R e so n a n c e S i g n a l
~ IU
■ 300
v ii
A b s tra c t
A K -band e l e c t r o n p a r a m a g n e tic r e s o n a n c e s p e c t r o m e t e r w as c o n s t r u e t e d i n o r d e r t o d e te r m in e t h e h ig h and lo w f i e l d g - v a l u e s , l i n e s h a p e s ,
an d l i n e w i d t h s f o r t h e s p e c t r a o f d i v a l e n t c o p p e r i n e th y la m m o n iu m - te tr a c h l o r o c u p ra te , and m eth y la m m o n iu m -te t r a c h l o r o c u p r a t e . The g - t e n s o r s
w e re d e te r m in e d t o b e g
= 2 . 053 , g
= 2 . 06 ? , and g
= 2 . 26l f o r e t h y l a m m o n iu m - te tr a c h lo r o c u p M te and gx x ^ 2 . 05 h , g
= 2 . § § 7, a n d gz z = 2.271
f o r me th y la m m o n iu m -te t r a c h l o r o c u p r a t e . An e x c h a n g e f r e q u e n c y o f 2 0 .3 9 GHa
f o r e t h y !am m onium -t e t r a c h l o r o c u p r a t e a n d 17. US GHz f o r me t h y !am m onium t e t r a c h l o r o c u p r a t e was c o m p u te d . D a ta w as a l s o t a k e n o n a c e ta m id in iu m t e t r a c h l o r o c u p r a t e t o c o n f ir m e a r l i e r f i n d i n g s .
C h a p te r I : I n t r o d u c t i o n “
E l e c t r o n p a r a m a g n e tic r e s o n a n c e (EPR) h a s b e e n a u s e f u l t o o l o f t h e
s p e c t r o s c o p i s t s i n c e t h e f i r s t e x p e r im e n ts o f Z a v o is k y i n 1914 *.1
The im ­
p r o v e m e n ts i n m icro w av e e q u ip m e n t h a v e g i v e n c o n t i n u i n g - i m p e t u s t o t h e
a p p l i c a t i o n o f EPR t o t h e s o l u t i o n o f p r o b le m s i n a w id e r a n g e o f d i s c i ­
p l i n e s , i n c l u d i n g b i o l o g y , c h e m i s t r y , e n g i n e e r i n g and p h y s i c s .
C la s s i c a ll y , th e
s p in n i n g e l e c t r o n i n a m a g n e tic f i e l d h a s b e e n com­
p a r e d t o a s p in n i n g t o p p r o c e s s i n g i n t h e g r a v i t a t i o n a l f i e l d o f t h e
e a rth .
2
A s im p le q u an tu m m e c h a n ic a l t r e a t m e n t w i l l b e g iv e n h e r e .
Con­
- g / % ^ a s s o c i a t e d w i t h t h e s p i n , “s', o f an
s i d e r t h e m a g n e tic m om ent,
e l e c t r o n , w h e re g i s t h e s p e c t r o s c o p i c s p l i t t i n g f a c t o r o r L ande g - f a c t o r
( 2 .0 0 2 3 f o r f r e e e l e c t r o n s )
IO "20 e r g / g a u s s ) . ^ ’ ^
and
/ ? i s t h e B o h r m ag n e to n (Xv7 = 0 .9 2 7 3 1 x
Q uantum m e c h a n ic a l ly , J i c a n assum e 25 + I d i s c r e t e
o r i e n t a t i o n s i n a s t a t i c h om ogeneous m a g n e tic f i e l d , H0 , a c c o r d in g t o t h e
Zeem an i n t e r a c t i o n Hz = g /SjHq i S .
a n e n e r g y l e v e l i n t h e s y s te m .
E ach o f t h e o r i e n t a t i o n s c o r r e s p o n d s t o
A s m a ll p e r t u r b i n g m a g n e tic f i e l d , H1,
p e r p e n d i c u l a r t o Hq an d ” r o t a t i n g ” a b o u t Hq w i t h a f r e q u e n c y o) , p r o v i d e s
t h e e n e r g y f o r t r a n s i t i o n s among t h e s e l e v e l s .
The c o n d i t i o n , f o r r e s o n a n t
a b s o rp tio n i s
h i)
g iv e n b y t h e f o l l o w i n g e q u a t i o n :
P l a n c k ’ s c o n s t a n t ( 6 . 6 2 5 . 7 x IO " 2? e r g - s ) .
= g/9HQ, w h e re h i s
The z a x i s i s g e n e r a l l y c h o s e n
t o b e a lo n g t h e f i e l d HQ, w h i l e H1 i s a s m a ll l i n e a r l y o s c i l l a t i n g f i e l d
w h ic h a p p e a r s t o r o t a t e i n t h e p l a n e p e r p e n d i c u l a r t o H ^.
s o lv e d i n t o two c o u n t e r - r o t a t i n g f i e l d s , i n t h e
same p l a n e .
H1 can be r e ­
T he com ponent
w h ic h r o t a t e s o p p o s it e t o t h e L a rm o u r p r e c e s s i o n a l d i r e c t i o n h a s l i t t l e
e f­
f e c t ; h o w e v e r, t h e o t h e r co m ponent c a n b e a b s o rb e d and c a n ,c a u s e t r a n s i ­
tio n s .
The t e r m s f o r t h e H a m ilto n ia n c a n t h e n b e w r i t t e n a s f o l l o w s : ' Hz =
2
c o s P I T ^ t w h e re S 0 and Sx a r e t h e z and x a x i s
g/S’SgHo an d ^
p r o je c tio n s o f th e s p in ,
Sx c a n b e r e w r i t t e n a s S+ + S_ i f S+ and S_ a r e
and Scio — «p»tsa«w
------- 3ra»«3^«se
d e f i n e d a s f o l l o w s : S+
L e t [ m^
rep re sen t
a s t a t e o f t h e s y s te m , w h e re M i s th e e l e c t r o n s p in m a g n e tic nu m b er, and
o p e ra te on t h i s
s e t w i t h Hpe r -Jio
It
e r and lo w e r s p i n s t a t e s a r e p o s s i b l e ,
th e n seen t h a t t r a n s i t i o n s to h ig h ­
1P e r tc
|M> = g Z^H1c o s 2 IT tit | ( V S (S + I ) -M (M + I )
I 1>)J.
M -
g /5 % c o s 2 T hvt (S , + S „ )
IM + 1 > + V s ( S + l)-M (M - l )
The l i n e i n t e n s i t y o f t r a n s i t i o n p r o b a b i l i t y p e r u n i t tim e f o r
t h e s t a t e |]yi - 1>
i s p r o p o r t i o n a l t o t h e m a t r i x e le m e n t s q u a r e d .
In te n ­
s i t y /'vi |<M ~ I I Hpe r ^ I M>
[co s 2it',u t
^S(.S + l ) ■» M(M — l ) J
_X
--X
B r i e f l y , Hq s p l i t s th e s p i n d e g e n e r a te l e v e l s and H 1 p r o v i d e s t h e e n e rg y
f o r tra n s itio n s .
o f HI
.
T r a n s i t io n s ta k e p la c e o n ly i f th e r o t a t i o n a l fre q u e n c y
a b o u t t h e z a x i s i s t h e same a s t h e r o t a t i o n a l f r e q u e n c y ( L arm our
f r e q u e n c y ) o f t h e m a g n e tic m om ent.
I n a d d i t i o n t o th e m a g n e tic moment o f t h e e l e c t r o n , many a to m s h a v e a
n u c l e a r m a g n e tic moment w h ic h c a n b e d e f i n e d a s
th e n u c le a r s p in .
= g ^ /$ T I , w h ere I i s
The. e f f e c t o f t h i s te r m c a n b e c o n s i d e r e d a s a n i n t e r ­
a c t i o n p e r t u r b a t i o n •i n t h e H a m ilto n ia n and c a n b e w r i t t e n a s A S 'I , w h ere
A i s .a c o n s t a n t .
The n u c l e u s o f t h e c o p p e r ato m h a s a s p i n o f 3 / 2 w h ic h
s h o u ld g iv e a h y p e r f i n e s p e c tr u m ; h o w e v e r, e x p e r i m e n t a l l y t h i s i s c o n c e a le d
b y th e s p in - s p in b ro a d e n in g o f th e h y p e rf in e t r a n s i t i o n .
The e l e c t r o n i n a c r y s t a l l a t t i c e
i s n o t f r e e a s w as t h e c a s e i n t h e
‘
p r e c e d i n g d i s c u s s i o n ; i t i s c o n s t r a i n e d b y v a r i o u s i n t e r a c t i o n and b i n d i n g
fo rc e s.
The p a r a m a g n e tic i o n c o n s id e r e d i n t h i s t h e s i s was d i v a l e n t co p ­
p e r (Cu"^~).
C u^" i s i n t h e i r o n t r a n s i t i o n g ro u p and h a s a n e l e c t r o n i c co n ­
3
f i g u r a t i o n I s 2 s 2p 3 s 3 p 3 d ^ .^
I n s o l i d s t h e e l e c t r o n i c o r b i t a l m o tio n
i n t e r a c t s w i t h t h e c r y s t a l l i n e " e l e c t r i c f i e l d s and b eco m es d e c o u p le d f ro m
th e s p in .
T h i s . i s c a l l e d q u e n c h in g and i s a s t r o n g m ech an ism i n t h e i -
ro n g ro u p .
As a r e s u l t ,
ra te .
i n Cu^" t h e g ro u n d s t a t e i o n i s o n l y s p i n d e g e n e ­
The g ro u n d s t a t e i s t h e
- y2 o rb ita l.
F i g u r e One shows a s c h e .
z
m a t ic d ia g r a m o f t h e e n e r g y l e v e l s o f d i v a l e n t c o p p e r !
T h is f ig u r e
shows
t h a t t h e f r e e i o n l e v e l i s o r b i t a l l y f i v e - f o l d d e g e n e r a te and tw o - f o l d
s p in d e g e n e ra te .
fie ld ,
it
When t h e i o n i s p l a c e d i n a c u b i c a l l y s y m m e tric e l e c t r i c
s p l i t s i n t o tw o e n e r g y l e v e l s ,
f o ld o r b i t a l l y d e g e n e ra te .
t h e t o p one o f w h ic h i s t h r e e ­
The a d d i t i o n o f a t e t r a g o n a l com ponent t o t h e
e l e c t r i c f i e l d f u r t h e r re d u c e s th e o r b i t a l d e g e n e ra c y .
b i t c o u p li n g e l i m i n a t e s t h e o r b i t a l d e g e n e r a c y .
tic fie ld
F in a lly ,
s p in o r ­
A p p l i c a t i o n o f a m agne­
rem o v e s t h e s p i n d e g e n e r a c y o f a l l l e v e l s b u t i s shown h e r e o n l y
f o r th e lo w e s t le v e l.,
The J a h n - T e l l e r th e o r e m s t a t e s t h a t a c r y s t a l l a t t i c e w i l l d i s t o r t
3 7
t o rem ove a s much d e g e n e r a c y a s p o s s i b l e . ’
if
K ra m e r’ s th e o r e m s t a t e s t h a t
t h e r e a r e a n odd n u m b er o f e l e c t r o n s i n t h e s y s te m , no e l e c t r i c f i e l d
c a n rem ove a l l t h e d e g e n e r a c y o f t h e s t a t e s . ^
f o r e a p p l i c a t i o n o f t h e m a g n e tic f i e l d
The g ro u n d s t a t e o f Out^ b e ­
i s d o u b ly d e g e n e r a te and i s s p l i t .
8^ 2 cm” -1- fro m t h e n e a r e s t e x c i t e d o r b i t a l s t a t e . ^
A t room t e m p e r a t u r e on­
l y a fe w e l e c t r o n s h a v e e n o u g h e n e r g y t o g.ump an e n e r g y gap o f .m o r e t h a n
250 cm""*" so t h a t t h e r e a r e v e r y fe w e l e c t r o n s o c c u p y in g t h e e x c i t e d o r b i ­
t a l le v e ls .
T h e r e f o r e , t h e o n l y e x t e n s i v e l y p o p u la te d l e v e l s a r e t h e s p i n
d e g e n e r a te g ro u n d o r b i t a l s i n g l e t s t a t e .
N um bers on e a c h e n e r g y l e v e l i n d i c a t e
o r b i t a l and s p i n d e g e n e r a c y r e s p e c t i v e l y
o f each l e v e l .
2X2
/
/
3X2
\
1X2
5X2
1X2
\
2 X 2
\
/
1X2
/
T
\
FREE
ION
CUBIC FIELD
TETRAGONAL SPIN- APPLIED
FIELD
ORBIT FIELD
COUPLING
F ig u re I .
E n e rg y l e v e l d ia g ra m f o r d i v a l e n t c o p p e r
C h a p te r I I :
.Li.
Ctii t
EPR o f C o p p e r C om plexes,
_
i s o n e o f t h e i d e a l i o n s f o r p a r a m a g n e tic r e s o n a n c e s i n c e t h e r e
i s o n l y one e l e c t r o n i c t r a n s i t i o n and n a rr o w l i n e s c a n b e o b t a i n e d a t room
te m p e ra tu re s .
H i s t o r i c a l l y , m o st new d i s c o v e r i e s a s s o c i a t e d w ith s o l i d
w ave s p e c t r a h a v e b e e n f i r s t o b s e rv e d i n Cu^
s a lts .
"The e f f e c t o f e x ­
c h a n g e f o r c e s w as f i r s t d i s c o v e r e d i n CuSOlr^HgO; t h e
fin e
s t a t e m ic r o -
e x is te n c e o f h y p e r-
s t r u c t u r e w as f i r s t o b s e r v e d i n a d i l u t e d c o p p e r s a l t ;
t h e q u a d r a p o le i n t e r a c t i o n w as f i r s t n o t i c e d i n t h e C u^
th e e f f e c t o f
h y p e rfin e spec­
tru m ; h e a v y w a t e r w a s f i r s t u s e d w i t h c o p p e r T u t to n s a l t c r y s t a l s t o r e ­
s o lv e o u t t h e i s o t o p e s p l i t t i n g ; t h e c o n c e p t o f a r e s o n a t i n g c r y s t a l f i e l d
w as f i r s t i n t r o d u c e d t o a c c o u n t f o r t h e c o p p e r f I u o s i l i c a t e
s p e c tru m ; and
m e a s u re m e n ts o n c o p p e r a c e t a t e w e re t h e f i r s t t o show t h a t two p a ra m a g n e ­
tic
i o n s c o u ld i n t e r a c t s t r o n g l y t o fo rm a com bined s y s te m o f e n e r g y I e -
v e ls ." £
E th y l a m m o n i u m - t e tr a c h l o r o c u p r a te
a m m o n iu m - te tr a c h lo r o c u p r a te
[ mATCC,
[ e ATCC,
(
(CH3NH3 ) 2 C u C l^ j
gCuc l ^ j
h av e b e e n s tu d ie d
to o b ta in p r e lim in a r y in fo r m a tio n r e g a r d in g th e g v a lu e s , l i n e
l i n e w i d t h s a t room t e m p e r a t u r e s .
9
and m e t h y l-
s h a p e s , and
T he p r e s e n t w ork h a s shown p r e v i o u s l y
fo u n d g v a l u e s t o b e i n c o r r e c t b e c a u s e t h e g v a l u e s te n d e d to w a r d s W i l l e t t ’ s
f o r m is a ll ig n m e n t o f t h e c r y s t a l .
10
I n a d d i t i o n , t h e l i n e w i d t h s and l i n e
s h a p e s w h ic h w e re d e te r m in e d i n t h i s w o rk d i d n o t a p p e a r i n t h e p r e v i o u s
re s u lts .
The u n u s u a l "tw o d im e n s io n a l" c r y s t a l s t r u c t u r e fo u n d i n EATCC and
MATCC h a s s t i m u l a t e d i n t e r e s t i n t h e s e a n d o t h e r s i m i l a r c r y s t a l s .
6
F i g u r e Two show s an e x a g g e r a te d an d d i s t o r t e d o c t a h e d r a l sy m m e try •
p a r t i c u l a r t o EATGC and MATCCo
The a x e s x , y , and z a r e a s s o c i a t e d w i t h
th e s h o r t e s t to lo n g e s t bonds r e s p e c ti v e ly .
I n MATCC and EATCC, t h e bond
l e n g t h s a r e x = 2 .3 0 0 S , y_= 2 .3 3 2 S a n d z = 2 .7 9 3
t e t r a c h l o r o c u p ra te
I n a c e ta m id in iu m -
(ACTCC,
a r e a p p r o x i m a t e ly e q u a l an d t h e z bond l e n g t h i s l o n g e r .
F i g u r e T h r e e , a . a n d b . p o i n t s o u t t h e s t r u c t u r e i n EATCC, MATCC,
a n d ACTCC.
The b r o a d f a c e o f t h e c r y s t a l s i s p a r a l l e l t o t h e p l a n e o f t h e
p a p e r i n F ig u re T h re e .
The z a x i s i n a . i s t h e lo n g bond and i n b . t h e
z a x i s i s p e r p e n d i c u l a r t o t h e p l a n e show n.
a s d o t s i n b o t h a . and b .
The C u ^
io n s a r e .r e p r e s e n te d
The c h l o r i n e i o n s c a n b e t h o u g h t o f a s a p p e a ­
r i n g a t t h e en d o f e a c h l i n e a r bond r e p r e s e n t a t i o n i n a . an d i n t h e m id d le
o f e a c h l i n e a r r e p r e s e n t a t i o n in ' b .
The d a t a fro m t h e w o rk o n EATCC and MATCC h a s b e e n u s e d f o r a p r e l i ­
m in a r y s tu d y o f t h e e x c h a n g e m ech an ism b e tw e e n t h e C u ^
b rid g e .
i o n s w i t h C l" a s a
T h i s e x c h a n g e m ech an ism i s g e n e r a l l y r e f e r r e d t o a s " s u p e r e x ­
c h a n g e ." ^
T h is d a ta w i l l l a t e r be u se d a s p a r t o f a fre q u e n c y d ep en d en t
s tu d y o f g v a l u e s .
ACTCC w as s t u d i e d t o c o n f ir m t h e e x i s t e n c e o f a se c o n d
m a g n e tic a x i s i n t h e c r y s t a l .
9 ,1 2 ,1 3
The g v a l u e s o f ACTCC h a v e b e e n m ea-
s u r e d an d a r e i n c l u d e d w i t h t h e r e s u l t s .
sh a p e i s a l s o i n c l u d e d
12
A r e p r e s e n t a t i v e ACTCC l i n e
7
z a x is
Cl
x a x is
F ig u re 2 .
>y a x i s
D i s t o r t e d O c t a h e d r a l Sym m etry P a r t i c u l a r t o SATCC and MATCC
z>z
X
V
yz
H0
9 max.
plane
-e----- long
xy
bond
-©-----short bonds
CU
F ig u re 3 - a .
I
C r y s t a l S t r u c t u r e o f 2ATCC, KATCC
plane
CU
F ig u re 3 -b .
C r y s t a l S t r u c t u r e o f ACTCC
C h a p te r I I I :
E x p e r im e n ta l R e s u l t s
EATCC5 MATCC5 and AGTCC w e re s t u d i e d w i t h t h e k~band .s p e c tr o m e te r .
The maximum a n a minimum ' g v a l u e s 5 l i n e w i d t h s 5 and l i n e
f o r EATCC an d MATCC,
I n a d d i t i o n , t h e e x i s t e n c e o f a se c o n d m a g n e tic a x i s
i n ACTCC w as c o n firm e d w i t h t h i s s p e c t r o m e t e r .
T a b le I and i n F i g u r e s F o u r th r o u g h S i g h t .
G a u s s ia n l i n e
s h a p e s .w ere t a k e n
T h is d a t a i s p r e s e n t e d i n
The t h e o r e t i c a l L o r e n t z i a n and
s h a p e s a r e s u p e rim p o s e d o n t h e e x p e r i m e n t a l l i n e
EATCC and MATCC.
sh ap es o f
( I t s h o u ld b e n o t e d t h a t i n o p p o s i t i o n t o t h e u s u a l c u s ­
tom , ' t h e t h e o r e t i c a l s h a p e s a r e r e p r e s e n t e d a s c i r c l e s a n d . c r o s s e s w h ile
th e e x p e rim e n ta l d a ta a re c o n tin u o u s .
T h is i s b ecau se th e e x p e rim e n ta l
d a t a a r e t r a c e d fro m t h e c h a r t r e c o r d e r o u t p u t o f th e s p e c t r o m e t e r .)
.
;
TABLE I
C ry s ta l
g m in
g max
EATCO '
2 .0 5 3
2 . 16 U
W
.EATCC
2 . OUli
■
-
l i n e w id th
g m in g a u s s
8 0 .2
MATCCw
ACTCC1
2 .0 5 U .
'
' 2 . 0 U6
2.0U 7
2 .3 3 7 e x c h .
gH 2 .3 5 5 i s o l .
8I4. I
’
2 .1 3 7 .
.
MATCC
l i n e w id th
g max g a u s s
.
2 .1 6 9
'
9U .9
.
..
- i-
. .'
> 9 .lt .
■
2.1U 3
• 2 . 1 U1
2.061
2 .0 6 3
- •
■
•.
'•
:•
W-The d a t a o f W i l l e t t e t a l . on EATCC5 MATCC i s in c lu d e d , f o r c o m p a r is o n .1^ ■
i
(C0 He-Ni-L)0 Cu Cl
LOW FIELD
EXP.
(g man.)
CURVE
THEOR. GAUSSIAN
TH E O R . LO RENTZIAN
7850
8000
8150
8300
GAUSS
Figure iu
EATCC
8450
8600
■
H! FIELD
EXP
(g min)
CURVE
THEOR.
GAUSSIAN
THEOR. LORENTZIAN
8250
8400
8550
8700
GAUSS
Figure 5.
EATCC
8850
9000
(CH3 NH3)2 Cu Cl4
LOW FIELD
(g max.)
EXP. CURVE
THEOR.
GAUSSIAN »
THEOR. LORENTZIAN
7950
8150
8350
8550
GAUSS
Figure 6 .
MTCC
8750
(CHzrNH^l)Cu Cl
HI FIELD (g m in.)
EXP. CURVE
TH EO R . GAUSSIAN
THEOR. LORENTZIAN -
8200
8500
GAUSS
8650
Figure 7 .
MATCC
8800
(CH3 C(NH2 )2 )CuCI4
HI FIELD
9000
_____I__________
8500
8000
_____ I_________
Figure 8.
ACTCC
7500
15
The g v a l u e s in. HATGC and EATCC a r e a n i s o t r o p i c and a r e c h a r a c t e r i z e d
b y t h e g t e n s o r w hich h a s t h e p r i n c i p a l v a l u e s g ^ ,
g
.
z a x i s i s t h e l o n g bond a x i s o f t h e d i s t o r t e d o c ta h e d r o n .'
a n d g z z w h ere t h e
O f te n t h i s t e n -
s o r h a s a x i a l sy m m etry , i n w h ic h c a s e Ex x = Ey y = Ei . a n d g zz = g,, .
w as t h e a s s u m p tio n made b y W i l l e t t e t a l . 11
re la te d
T h is
S in c e t h e e l e c t r o n g v a lu e i s
t o t h e C u -C l bond l e n g t h and s i n c e x i s n o t e q u a l t o y i n EATCC
a n d MATCC, i t i s t o b e e x p e c t e d t h a t g
w o u ld n o t e q u a l g . S in c e g
y
jqc
yy
Sm ln = 'S i
a n d i ( g y y + g ^ ) = g ^ x , w h e re
i n o r d e r t o d e te r m in e g,| .
=
= g„ , g ^ m u st b e d e te r m in e d
S in c e x i s r e l a t e d t o g
, e t c . i t w a s th o u g h t
t h a t Eltiax m u st b e r e l a t e d t o
T h i s w as c o n firm e d b y c a l c u l a t i o n s
w ith
e . U s in g a g r a p h i c a l s o l u t i o n , t h e
a s r e l a te d to
d a t a t a b u l a t e d i n T a b le I I w a s o b t a i n e d .
TABLE I I
C ry s ta l
^x x
EATCC
MATCC
gyy
Szz = S|,
2 .0 5 3 .
2.067
2.261
2 .0 5 5
2 .0 6 8
Sj
'
2.270
Tlo I Vi
The d a t a i n T a b le I I l e a d s t o t h e c o n c l u s i o n t h a t t h e r a t i o o f t h e
s q u a r e r o o t o f t h e b o n d l e n g t h s i s a p p r o x i m a t e ly e q u a l t o t h e r a t i o o f t h e
g v a lu e s .
The C u -C l-C u p a r a m a g n e tic e l e c t r o n s u p e r e x c h a n g e f r e q u e n c y h a s b e e n ■
'
16
c a l c u l a t e d u s i n g t h e f o l l o w i n g c a l c u l a t i o n fro m F a k e :
^ d 2 =
= (3 /b )S (S + l ) t
24 g ^ ^ r . ,
J
J jc
^ ( 3 c o s 2 (9'
s p i n quantum num ber w h ic h i s e q u a l t o J f o r C u ^
jk
©
- I )2
w h e re S i s t h e
, g = 2 . 16 I4 f o r EATCC and
2.169 f o r MATCC5 r i s t h e d i s t a n c e b e tw e e n t h e C u^
10 "® cm,
3
i o n s a n d i s 3.125) x
i s t h e a n g le fro m t h e z a x i s o f a t y p i c a l i n t e r i o r i o n s i t e
k t o a n y o t h e r i n t e r a c t i n g ato m j ,
t h e sum b e i n g c a r r i e d o u t o v e r t h e n e a ­
r e s t n e i g h b o r s i t e s o n l y , a n d CJcJ i s t h e d i p o l a r e x c h a n g e f r e q u e n c y ,
A ( J i = -*y=
2
c-
w h e re A C J i i s t h e a n g u l a r f r e q u e n c y h a l f w id th a n d . <D
Wg
2
i s t h e C u -C l-C u e l e c t r o n s u p e r e x c h a n g e f r e q u e n c y .
e
A G d i. 2
A H i i s t h e l i n e w i d t h i n g a u s s a t h a l f maximum a m p l it u d e .
w h ere
n
2
F in a lly , A H i
2
= -VrJ A H
. w h e re A H
i s t h e p e a k t o p e a k l i n e w id th
. pp’
PP
2
g iv e n i n T a b le I .
The c a l c u l a t e d v a l u e s o f Cde a r e , f o r EATCC and MATCC r e s p e c t i v e l y ,
GHz an d 1 7 . U8 GHz.
2 0 .3 9
3
C h a p te r IV :
The S p e c tr o m e te r
The S p e c tr o m e t e r
The k -h a n d s p e c t r o m e t e r c o n s t r u c t e d f o r t h i s e x p e r im e n t i s a h ig h
f r e q u e n c y m o d u la tio n s p e c t r o m e t e r u t i l i z i n g a r e f l e c t i o n c a v i t y .
d ia g r a m o f t h e s p e c t r o m e t e r i s
shown i n F i g u r e N in e .
A hM ck
M ost o f t h e s p e c t r o ­
m e t e r w as a s s e m b le d w i t h c o m m e rc ia lly m a n u f a c tu r e d e q u ip m e n t.
The p i e c e s
b u i l t " i n h o u s e " w e re t h e c a v i t y , t h e 125 KHz m o d u la tio n o s c i l l a t o r - a m p l i ­
fie r^
t h e m o d u la tio n c o i l s , t h e n u c l e a r m a g n e tic r e s o n a n c e (NMR) p r o b e ^
an d a lo w t e m p e r a t u r e c a v i t y m o u n t.
16
The k l y s t r o n i s a n OKI m o d el 2LiVlQA w h ic h c a n b e made t o o s c i l l a t e
o v e r t h e r a n g e 2 2 .0 t o 2 6 .0 GHz.
The k l y s t r o n i s m ounted i n a TRG m odel
9l|6A o i l b a t h m ount t o m a i n t a i n t h e k l y s t r o n a t a s t a b l e t e m p e r a t u r e l e v e l
a n d t h u s im p ro v e t h e f r e q u e n c y s t a b i l i t y . . T he k l y s t r o n i s p o w ered b y a N a r
d a M i c r o l i n e m o d el 621A p o w e r s u p p ly w i t h a K epco m o d el ABC v o l t a g e r e g u l a ­
t e d k l y s t r o n f i l a m e n t s u p p ly .
The k l y s t r o n f r e q u e n c y d r i f t i s c o n t r o l l e d
b y a T e l t r o n i c s m o d el KSLP k l y s t r o n s t a b i l i z e r w hich a p p l i e s " a 70 KHz s i g ­
n a l t o t h e r e f l e c t o r o f t h e k l y s t r o n , p h a s e d e t e c t s t h e o u t p u t , and p r o ­
v id e s a d .c . c o r r e c tio n v o lta g e to th e r e f l e c t o r .
The k l y s t r o n i s e f f e c ­
t i v e l y i s o l a t e d w i t h a minimum i s o l a t i o n o f 2Li db fro m a n y r e f l e c t e d m ic r o w a v e s b y t h e PHD m o d el 1209F1 i s o l a t o r .
b r a t e d a t t e n u a t o r ( 0 t o L|0 db)
o f th e k ly s tr o n .
The W a v e lin e , I n c . m odel 812 c a l i ­
s e r v e s t o r e d u c e th e e f f e c t i v e pow er o u t p u t
I t i s n e c e s s a ry to h av e an a tt e n u a t o r s in c e th e k l y s t r o n
i s a f ix e d pow er o u tp u t d e v ic e .
A W a v e lin e , I n c . m o d el 8 6 9 -2 0 db c r o s s g u id e c o u p l e r s p l i t s th e . s i g n a l
fro m t h e k l y s t r o n i n t o two s i g n a l s :
t h e l a r g e r o f w h ic h g o e s t o th e F e r r o -
t e c , I n c . m o d el T380 3 p o r t f e r r i t e
c i r c u l a t o r and t h e s m a l l e r o f w h ic h
,to y axis input scope
to lock in amplifier
klystron
pw rsup.
Iystrorr
in oil
fit.
pw r sup.
isolator
tuneable crystal mount
circulator
calibrated
atten uator
c rp ss
guide
coupler
slide scr e w tuner
to y axis InpUt
scope
crystal
mount
frequency
meter
directional coupler
and bolometer
modulation coils
to x axis input scope
\
to x axis in put scope
\ ,to modulation coils
ca v it y
4 0 0 hz
to lock in
amplifier
125 khz
OSC
/
to electronic
/
counter
to y a x is input s c o p e
Figure 9 .
K BAND REFLECTION
t
to modulation coils
SPECTROMETER
19
g o e s t o t h e N a rd a M icrow ave C o r p o r a t i o n m odel 1 0 6 8 -3 db d i r e c t i o n a l c o u p I e r ,,
The s i g n a l r e f l e c t e d fro m t h e c i r c u l a t o r r e t u r n s t o t h e c r o s s g u id e c o
c o u p l e r an d s p l i t s ,
p a r t o f w h ic h r e t u r n s t o t h e a t t e n u a t o r and th e o t h e r
p a r t o f w h ic h t e r m i n a t e s i n a W a v e lin e , I n c . m odel 85U m a tc h e d l o a d .
The 3 db d i r e c t i o n a l c o u p l e r s p l i t s t h e s i g n a l fro m t h e 2 db c r o s s
g u id e c o u p l e r i n t o two c o m p o n e n ts , one o f w h ich g o e s t o a H e w le tt- P a c k a r d
m o d el K332A p r e c i s i o n d i r e c t r e a d i n g f r e q u e n c y m e te r , and t h e o t h e r o f
w h ic h g o e s t o t h e FED m odel 621A b o l o m e te r .
The s i g n a l fro m t h e p r e c i s i o n
d i r e c t r e a d i n g f r e q u e n c y m e t e r c a n t h e n b e d e t e c t e d i n a W a v e lin e , I n c .
m o d el 8l 6 c r y s t a l m ount w i t h a 1N26 d i o d e .
g o e s t o t h e W a v e lin e , I n c . m o d el 883 s l i d e
c a v ity .
The s i g n a l fro m t h e c i r c u l a t o r
s c re w t u n e r and fro m t h e r e t o t h e
T he s l i d e s c re w t u n e r can b e t h o u g h t o f a s a v a r i a b l e im p ed an ce
w h ic h c a n b e a d j u s t e d t o m atc h th e im p e d a n ce o f t h e d e t e c t o r arm t o t h e im ­
p e d a n c e o f t h e c a v i t y arm .
t h e w a v e g u id e , i . e . ,
re fle c te d
I t s e f f e c t i s t o tu n e o u t a n y s t a n d i n g w aves i n
t o r e d u c e t h e p o w e r t r a n s f e r a lo n g th e w a v e g u id e .
r a d i a t i o n p a s s e s th r o u g h t h e s l i d e
The
s c re w t u n e r t o t h e c i r c u l a t o r
and fro m t h e r e t o t h e PRD m o d el 621AF t u n e a b l e c r y s t a l m o u n t, w h ic h i s a l s o
e q u ip p e d w i t h a 1N26 d e t e c t i o n d i o d e .
The a s s o c i a t e d e q u ip m e n t f o r t h e
c rib e d .
s p e c tro m e te r w i l l be b r i e f l y d e s ­
A T e k t r o n i x , I n c . ty p e 5>[£A o s c i l l o s c o p e w ith e i t h e r a ty p e B o r
ty p e E p l u g - i n u n i t w as u s e d t o m o n ito r t h e s i g n a l s fro m b o t h t h e t u n e a b l e
and f i x e d c r y s t a l m o u n ts , t h e 123 KHz m o d u la tio n and t h e s i g n a l fro m t h e
NMR p r o b e .
The 12$ KHz o s c i l l a t o r - a m p l i f i e r w as u s e d t o add a m o d u la te d ,
com ponent t o t h e s t a t i c m a g n e tic f i e l d .
F i g u r e s Ten an d E le v e n show t h e
c i r c u i t d ia g r a m s o f t h e o s c i l l a t o r - a m p l i f i e r and th e a m p l i f i e r .
The
/ Z N 3713
2 N 4124
2N3789
N3789
3 .3 K
2 .2 K
F ig u re 11.
1 2 5 KHZ AMPLIFIER
CHANNEL 2
IOOO
IN33I9
2N277
15000'
JN I200A
2 N 2 7 7 5 SO
I
fy
OUTPUT TO
CHANNEL 2
"W W O
O
600,
OUTPUT
Figure 10.
I25KHZ
O S C IL L A T O R
AMPLIFIER
15000
22
The n u c l e a r m a g n e tic r e s o n a n c e (NMR) p ro b e w as u s e d t o d e te r m in e a n
a c c u r a t e v a l u e o f t h e m a g n e tic f i e l d
a t r e s o n a n c e and a H e w le tt- P a c k a r d
m o d el 52 li6L e l e c t r o n i c c o u n t e r w as u t i l i z e d t o d e te r m in e t h e o s c i l l a t i o n
f r e q u e n c y o f t h e NMR o s c i l l a t o r .
The H e w le tt- P a c k a r d m odel 200 AB a u d io
o s c i l l a t o r w as u s e d t o m o d u la te t h e m a g n e tic f i e l d a t h00 H z.
A P r in c e ­
t o n A p p lie d R e s e a rc h C o r p o r a t i o n m o d el 121 l o c k - i n a m p l i f i e r / p h a s e d e t e c t o r
(PAR) w a s u s e d t o d e t e c t t h e a b s o r p t i o n o f e n e r g y fro m t h e m icrow ave f i e l d
i n th e c a v ity a t reso n a n c e .
B o th a V a r ia n m o d el G I ljA - I g r a p h i c r e c o r d e r
and a H e w le tt- P a c k a r d m odel 7000 AR x - y r e c o r d e r w ere u s e d t o r e c o r d t h e
d a ta .
A F i e l d i a l m o d el VFR2f>03 V a r ia n f i e l d
r e g u l a t e d m ag n e t pow er s u p p ly
w as u s e d t o c o n t r o l a V a r ia n m o d el V - 3 I4OO e le c t r o m a g n e t .
A v a r i a b l e t e m p e r a t u r e c a v i t y m o u n t, shown i n F i g u r e T w e lv e , w as u s e d
a t room t e m p e r a t u r e .
T h i s m ount w i l l a l s o b e u s e d t o s u p p o r t th e c a v i t y
i n low t e m p e r a t u r e d e w e rs f o r p o s s i b l e v a r i a b l e t e m p e r a t u r e w o rk .
The
f i x e d f r e q u e n c y c a v i t y w as d e s ig n e d t o r e s o n a t e a t 2lj..7 GHz.
The T E 011 r e s o n a n t mode w as c h o s e n f o r c e n t r a l p o s i t i o n i n g o f t h e c r y ­
s t a l i n t h e r e g i o n o f maximum m a g n e tic f i e l d
th e e l e c t r i c f i e l d .
n e tic f ie ld
tic fie ld ,
and minimum i n t e r f e r e n c e w i t h
A s c a n b e s e e n i n F i g u r e T h i r t e e n , t h e p e r t u r b i n g mag­
i s a lw a y s p e r p e n d i c u l a r t o t h e l e v e l s p l i t t i n g (Zeem an) m agne­
th u s a llo w in g th e r o t a t i o n o f th e f i e l d
ab o u t th e v e r t i c a l a x is
w i t h no l o s s i n i n t e n s i t y .
The c a v i t y u s e d w as c o n s t r u c t e d i n t h r e e s t e p s :
I . A .6 0 0 in c h i n n e r
d i a m e t e r h o l e w as c u t i n b r a s s s t o c k , t h e o u t e r s u r f a c e o f w h ic h w as c u t t o
.63U i n c h e s .
p la s tic .
2 . A .6 5 0 i n c h i n n e r d i a m e te r h o l e was c u t i n lo w t e m p e r a t u r e
3 . W ith t h e p l a s t i c p i e c e c e n t e r e d i n t h e l a t h e ,
t h e b r a s s w as
iris tuning control
- c r y s t o l positioning rod
waveguide
cavity evacuation tube
_— " c o o le n t input tube
dewer evacuation tube
cavity
F ig u re 1 2 .
V a r i a b l e T e m p e ra tu re C a v i ty M ount
PROBE
E fie ld
H fie ld
plastic body
brass liner
iris plate
choke plate
F ig u re 13.
CYLINDRICAL
T E qm
CAVITY
25
c o o le d w i t h l i q u i d a i r and f o r c e d i n t o t h e p l a s t i c .
o f t h e b r a s s w as t h e n m ac h in e d t o
The i n n e r d i a m e te r
,650 i n c h e s a n d t h e e n d s o f t h e p l a s t i c
w i t h t h e b r a s s l i n e r w e re f a c e d so t h e l e n g t h o f t h e p i e c e w as .650 i n c h e s .
A b r a s s end p l a t e w as m a c h in e d w i t h a q u a r t e r wave ch o k e f o r o n e end o f t h e
c a v i t y and a c o p p e r p l a t e w i t h an i r i s h o l e .1 3 i n c h e s i n d i a m e te r c e n t e r e d
a t a p p r o x i m a t e ly h a l f t h e r a d i u s o f t h e d i s c w as p o l i s h e d f o r t h e i n p u t
end.
2 5 ,0 0 0 i s t h e t h e o r e t i c a l maximum Q f o r a c a v i t y o f t h i s d e s i g n .
The c a v i t y h a s a Q o f a b o u t 9 ,0 0 0 .
17
26
O peration o f th e Spectrom eter
The sta r t-u p procedure f o r the o p eration o f the K-band spectrom eter
i s as fo llo w s :
The power sw itch o f the k ly str o n supply i s turned on a f t e r notin g
th a t the overload sw itch i s on 2 5 ma„, the grid s e le c t sw itch i s on -300
v o l t s , the grid v o lta g e d i a l i s turned a l l the way up, the r e f le c t o r
v o lta g e d ia l i s a t about 300 v o lt s , and the beam v o lta g e d i a l i s at the
minimum p o s it io n .
The power sw itches o f the o s c illo s c o p e , th e PAR, the
125 KHz and bOO Hz o s c i l l a t o r s , and the k ly str o n s t a b ili z e r are a l l turned
on.
At t h is tim e th e beam ready li g h t on the k ly str o n power supply should
be l i t and the beam v o lta g e (m eter v alu e) should be in crea sed to 2000
v o l t s . The grid v o lta g e should then be reduced u n t il the beam current me­
t e r reads approxim ately 10 ma. (100 v o l t s upper d i a l ) .
The s ig n a l from
the mod. out jack o f the k ly str o n power supply should be taken to the hor­
iz o n t a l input o f the o s c illo s c o p e .
The modulator sw itch o f th e power sup­
p ly should be turned to the sin e wave and th e amplitude d ia l to about 150.
The h o r iz o n ta l d is p la y on the o s c illo s c o p e should be s e t on e x t . x 10 and
th e x a x is d riv e should be connected to th e tuneable c r y s t a l d e te c to r w ith
the v a r ia b le v o lts /c m on 0 . 5 .
The tuneable i r i s , the s lid e screw tuner,
and the tuneable d e te c to r can then be tuned f o r maximum s ig n a l.
r
The k ly -
stron should then be ad ju sted so the c a v ity i s in the middle o f the mode.
That i s so the o s c illo s c o p e tr a c e lo o k s lik e the trace in Figure Fourteen.
That the dip i s a c tu a lly the c a v ity and not a spurious s ig n a l from .
th e wave guide can be checked by moving th e te flo n c r y s t a l mount in and
out o f the c a v ity .
I f the d ip in the o s c illo s c o p e i s
a c tu a lly caused by
F i g u r e I I 4.
K l y s t r o n Mode w i t h C a v i ty R eso n an ce
28
th e
c a v i t y i t " w ill move fro m s i d e t o s id e i n t h e mode a s t h e c r y s t a l m ount
i s moved..
iWhen th e c a v i t y d i p i s c e n te r e d i n t h e k l y s t r o n mode w i t h t h e c r y s t a l
sam p le i n p o s i t i o n ,
t h e c a b le fro m t h e t u n e a b l e d e t e c t o r t o t h e o s c i l l o ­
sc o p e s h o u ld b e r u n t h r o u g h t h e k l y s t r o n s t a b i l i z e r and t h e s t a b i l i z e r
s w itc h e d t o t u n e .
I n o p e r a tio n , th e k ly s tr o n s t a b i l i z e r ad d s a c o rre c ­
t i o n to th e r e f l e c t o r v o lta g e to c o n tr o l th e o s c i l l a t i o n fre q u e n c y o f th e
k l y s t r o n an d t h e r e f o r e t h e k l y s t r o n s h o u ld h o l d on t h e r e s o n a n t f r e q u e n c y
o f th e c a v ity .
The m o d u la tio n o u t p u t a m p litu d e o f t h e N a rd a pow er s u p p ly s h o u ld t h e n
b e d e c r e a s e d , m a i n t a i n i n g t h e d i p i n t h e c e n t e r o f t h e s i g n a l by, a d j u s t i n g
th e r e f l e c t o r v o lta g e .
When t h e s i g n a l a m p litu d e h a s b e e n re d u c e d b y a
f a c t o r o f t e n o r s o , t h e m o d u la tio n c a n b e
t u r n e d o f f an d t h e k l y s t r o n
s t a b i l i z e r t u r n e d t o r e v e r s e o r n o rm a l AC l o c k .
The r e f l e c t o r v o l t a g e
s h o u ld t h e n b e a d j u s t e d u n t i l t h e c o r r e c t i o n v o l t a g e g o e s t o 0 .
The c o r ­
r e c t i o n v o l t a g e s h o u ld go p o s i t i v e o r n e g a t i v e w ith o r i n o p p o s i t e s e n s e t o
t h e r e f l e c t o r d i a l m ovem ent.
"When t h i s h a p p e n s , t h e k l y s t r o n s t a b i l i z e r i s
l o c k e d t o t h e c a v i t y and t h e s i g n a l l e a d t o t h e o s c i l l o s c o p e c a n b e t r a n s ­
f e r r e d . t o t h e s i g . i n j a c k o f t h e PAR..
The s l i d e
sc re w t u n e r s h o u ld t h e n b e tu n e d f o r maximum c r y s t a l c u r ­
r e n t on th e k l y s tr o n s t a b i l i z e r m e te r.
The PAR s h o u ld t h e n b e c a l i b r a t e d
a c c o r d in g t o t h e p r o c e d u r e o n p a g e s I I I - 3
e l.
and I I I - L o f t h e i n s t r u c t i o n m anu-
The w a t e r v a l v e s w h ic h l e t w a t e r f l o w t h r o u g h t h e e l e c tr o m a g n e t s h o u ld
b e o p e n e d so t h e p r e s s u r e on t h e d i a l (w h ic h r e a d s t h e lo w e r p r e s s u r e ) r e a d s
a b o u t 15> P S I .
The m a s t e r w a l l s w itc h p o w e rin g t h e e le c t r o m a g n e t s h o u ld b e
29
t u r n e d o n , t h e f i e l d i a l c o n t r o l u n i t s h o u ld b e t u r n e d on and f i e l d a d j u s ­
t e d t o a b o u t 8000 g a u s s f o r warm u p .
The V a r ia n g r a p h i c r e c o r d e r s h o u ld b e t u r n e d o n ( w i t h t h e p a p e r d r i v e
o ff).
The NMR"box s h o u ld b e t u r n e d o n and t h e p ro b e p o s i t i o n e d a s n e a r
to th e c a v ity a s p o s s ib l e .
( F i v e t u r n s o f num ber 20 w ir e w e re u s e d t o make
t h e r e s o n a n t c o i l f o r p r o t o n r e s o n a n c e i n t h e m a g n e tic f i e l d
r a n g e 75)00 t o
9000 g a u s s .)
The c o u n t e r s h o u ld b e t u r n e d on and t h e NMR b o x h o o k e d t o t h e c o u n t e r
an d t h e y a x i s i n p u t o f t h e o s c i l l o s c o p e .
The ItOO Hz m o d u la tio n f i e l d
s h o u ld b e c o n n e c te d t o t h e s m a l l e r w i r e c o i l s i n t h e e le c tr o m a g n e t and t o
th e h o r iz o n t a l in p u t o f th e sc o p e.
The r e s o n a n c e s i g n a l o f t h e NMR b o x
l o o k s som ew hat l i k e F i g u r e F i f t e e n , w i t h t h e p r o p e r a m p litu d e ItOO Hz- modu­
la tio n .
VJhen t h e e q u ip m e n t i s a l l r u n n in g , t h e r e c o r d e r i s c e n t e r e d and t h e
p a p e r d riv e s t a r t e d .
A t t h a t tim e t h e f i e l d i a l m ag n et sw eep i s
s ta rte d .
A r e a s o n a b l e sw eep tim e f o r i n i t i a l c h e c k o u t i s f i v e m in u t e s , w i t h a sw eep
r a n g e o f 1000 g a u s s .
30
F ig u re 1 $ .
NMR R e so n a n c e S i g n a l
APPENDIX
A p p e n d ix
E x p e r im e n t a l a b s o r p t i o n a n d / o r e x p e r i m e n t a l a b s o r p t i o n d e r i v a t i v e
c u r v e s a r e g e n e r a l l y o b t a i n e d i n EPR„
T h is d a t a u s u a l l y f o l l o w s t h e s h a p e
o f t h e t h e o r e t i c a l L o r e n t z i a n c u rv e t o a good a p p r o x im a tio n .
T h e o re tic a l
d a t a p o i n t s w i l l b e g iv e n f o r b o th G a u s s ia n and L o r e n t z i a n a b s o r p t i o n a n d
a b s o rp tio n d e r iv a tiv e l in e
shapes.
t o d e te r m in e w h e th e r a l i n e
T h i s n u m e r i c a l d a t a c a n .b e u t i l i z e d
sh a p e i s G a u s s ia n o r L o r e n t z i a n o r n e i t h e r .
The f o r m u la e f o r t h e t h e o r e t i c a l l i n e
sh ap es a re a s fo llo w s :
G a u s s ia n
L o re n tz ia n
■
A b s o r p ti o n
y
I
A b s o r p ti o n
d e riv a tiv e
“2 cxye
I _
.
+ X2
2y x
( i + %2)2
•
w h e re y i s t h e a m p l it u d e , c i s a c o n s t a n t , and x i s a m e a s u re o f t h e l i n e
w id th .'
T he d a t a i n T a b le I I I
th e i n i t i a l a m p litu d e .
i s t a b u l a t e d i n te r m s o f t h e p e r c e n ta g e o f
I t c a n b e p l o t t e d on th e same s c a l e a s t h e e x p e r i ­
m e n ta l c u r v e o r th e e x p e r i m e n t a l d a t a ( a r b i t r a r y s c a l e ) c a n b e p l o t t e d
a g a i n s t t h e t h e o r e t i c a l d a t a t o d e te r m in e w h ic h l i n e
G a u s s ia n ) g i v e s t h e b e s t f i t t o a s t r a i g h t l i n e .
shape ( L o re n tz ia n o r
33
TABLE I I I
2
Type o f c u rv e
G a u s s ia n
L o re n tz ia n
a m p litu d e
A b s o r p ti o n
A b so rp .
D e riv .
A b s o r p ti o n
A b s o rp .
D e riv .
IO ^
* 1 .8 2
.0 6
2 .3 b
+ . 3 .0 0
.0 3
2 .9 5
20^
+ 1 .5 2
.1 1
2 .0 7
+ 2 .0 0
.0 6
2 .2 2
30^
+ 1 .3 1
.16
1 .8 8
+ 1 .5 3
.0 9
1 .8 1
+ 1 .1 5
.2 2
1 .7 b
+ 1 .2 2
.1 2
1 .5 8
# #
+ 1 .0 0
.2 7
1 .6 2
+ 1 .0 0
.16
1 .3 7
6o%
+
.8 6
.3 b
1 .5 0
+
.8 2
.2 0
1 .2 2
70^
±
.7 3
.b l
1 .3 9
+
.6 6
.2 b
1 .0 8
80^
+
.5 7
• b9
1 .2 6
+I
.3 0
..9 5
90^
+
.3 2
.6 1
1 .1 2
I
.3 2
.3 6
.8 2
0 .0 0
.8 5
.8 5
0 .0 0
.5 6
.5 6
100%
.
LITERATURE CITED
L i t e r a t u r e C ite d
1.
S . A. A l t s h u l e r and B . M. K osyrew 5 E l e c t r o n P a r a m a g n e tic R e so n a n c e .
New Y ork: A cad em ic P r e s s , 196 I4,
2.
G. E . P a k e , P a r a m a g n e tic R e s o n a n c e .
3.
C. P . P o o le , J R ., E l e c t r o n S p in R e s o n a n c e .
P u b l i s h e r s , 1967 .
U.
R. B . L e i g h to n , P r i n c i p l e s o f M odem P h y s i c s .
Book C o., 1 9 2 9 . --------------------------------------------- --
2«
D .J .E , In g ra m , S p e c tr o s c o p y a t R a d io and M icrow ave F r e q u e n c i e s .
Y o rk : P len u m P re"ss^'% 957T "~
“* ”
"
6.
P . H. L e P e r e , An X-Band El e c t r o n P a r a m a g n e tic R eso n a n c e Sp e c tr o m e t e r
and I t s A p p l i c a t i o n t o t h e S tu d y o f D i v a l e n t M anganeseT lin M agnearum ^
— — ------
7.
E . U. C ondon, H. O d ish aw , H andbook o f P h y s i c s .
B ook C o ., 1 9 2 8 .
8.
H. M. A s s e n h e im , I n t r o d u c t i o n t o E l e c t r o n S p in R e s o n a n c e .
P len u m P r e s s , 1 9 2 7 !
——— ——
r"
9.
A l l : c r y s t a l s w e re g r o w b y P r o f e s s o r K e n n e th E m erson o f t h e M o n tan a
S t a t e U n i v e r s i t y D e p a r tm e n t o f C h e m is tr y .
1962.
------— ------ —
New Y ork: ¥ . A. B e n ja m in , I n c . ,
New Y o rk : I n t e r s c i e n c e
New Y o rk : M cG raw -H ill
New
New Y o rk : M cG raw -H ill
New Y ork:
1 0 . . R. D. W i l l e t t , 0 . L . L i l e s , J r . , C. M ic h e ls o n , "The E l e c t r o n i c A b s o r­
p t i o n S p e c t r a o f M o n e ric C o p p er ( I I ) , C h l o r i d e s p e c i e s , ■and th e E l e c ­
t r o n i c S p in R e so n a n c e S p e c tru m o f t h e S q u a r e - P l a n e r C uC l^ I o n , 11 O r- .
g a n ic C h e m is tr y , 1 9 6 8 .
11.
R. D. W i l l e t t , " C r y s t a l S t r u c t u r e o f (NHl) pCuCL , "
c a l P h y s i c s , 1 9 6U.
12.
L . A. B a r e s , K. E m e rso n , and J . E. D r u m h e lle r , On t h e P r e p a r a t i o n and
S t r u c t u r e o f A c e ta m id in iu m - t e t r a c h l o r o c u p r a t e ( T l ) ! U n p h G n s h e d T T 968 .
13.
G. T . Rado and H. S o h l, M a g n e t i s m ,.Vp I . I .
1963.
1 )|.
D e s ig n e d and c o n s t r u c t e d b y F . J . B la n k e n b u r g .
12.
D. H. D ic k e y , The F o r b id d e n H y p e r f in e P a r a m a g n e tic R e s o n a n c e .
M o n tan a S t a t e U n i v e r s i t y , *i9oST~r~™ "~
l6 .
D e s ig n e d and c o n s t r u c t e d b y P r o f e s s o r J . E . D r u m h e lle r .
J o u r n a l o f C hem i­
New Y ork: A cadem ic P r e s s ,
■ ,
T h e s is ,,
36
17.
J . De J a c k s o n , C l a s s i c a l E l e c t r o d y n a m ic s .
S ons, I n c . , 1962. .
New Y o rk : J o h n W ile y and
M O N TA N A S T A T E U N IV E R SIT Y LtB RA R TFS
3 1762 100 1891 6
Am undson, P . H.
An e l e c t r o n p a r a ­
m a g n e tic r e s o n a n c e stu d ;
o f t h e eth y lam m o n iu m -,
m ethylam m onium , and
a c e ta m id in iu r a . . . . . . . .
N378
Am93
cop. 2
WAMK A N O
A D O m g##
/ S
Z
C o
%l