574 64 2MB
English Pages 46
m f m s m n m of the mghetic m m m
or s33
w \s>
H ’Brace Hiillips
4 thesis submitted in partial fulfillment of the requirements
for the degree of Doctor of Philosophy, in the Department of Physics, in the Graduate College of the State University of Iowa June, 195)0
ProQuest Number: 10992020
All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is d e p e n d e n t upon the quality of the copy subm itted. In the unlikely e v e n t that the a u thor did not send a c o m p le te m anuscript and there are missing pages, these will be noted. Also, if m aterial had to be rem oved, a n o te will ind ica te the deletion.
uest ProQuest 10992020 Published by ProQuest LLC(2018). C opyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C o d e M icroform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 0 6  1346
r / 3so PS59 O o jp 'ct‘
Ih© author is indebted to Dr. Arthur Roberts for suggesting this research problem, and for his con stant guidance, advice, and encouragement throughout the period of research. Grateful acknowledgement is also made to Mr. J. G. Sentinella, who constructed mar^r components of the Microwave spectrometer, and to other members of the Basics Dep&idmtent Staff who mad© m m valuable suggestions for solving problems which
arose.
O >
O
11
Chapter I
I
n
t
r
o
d
u
c
t
Chapter II
Magnetic Interactions in G
C
i S
o
n
*
1

^
*
3
Chapter III Apparatus and Procedure Chapter IV
Results and Conclusions
Appendix I
Method of Determining
Bibliography
13 .... for OGS ......... •*.»*»•««•* **••**
iii
23 37
Page 1 * ^lyperfine structure pattern for the J = X^2 6
transition of CX2S^\**, 33
2« 1aargj levels of OCS in a magnetic field .*....
11
3* Zeeman splitting of the J a 1^2, F = 3/2*“1/2 transition in Q
Q
S
^
*
*
*
*
*««••• 12
iu Schematic diagram of the aELerawave spectrometer, 1k 16
5>* Zeeman magnet 6 . Eecordinga of OGS*^ F m 3/2»l/2 transition with
and without a Zeeman field •
iv
21
%ahle
Page
33 X. Frequencies of OSS Zeeman Oomponen&Bs EKperimental ....* . U m GaXeulations of %
... ....**,.*. ****•.*...
for u « 0,07 and Curve C*
Tig. 3 XXX.
2k
.... .....
26
Calculations of gn for u =■ 0.07 and Curve B, Fig* 3 ******......... *
27
17. Calculations of gn for u » 0*07 and Curve A9
ng. 5
.. ............... 28
7, Calculations of g„ il for u = 0 and Carve C. Fig* 3
29
71. Calculations of gR for u = 0 and Curve B, Fig* 3 VII*
30
Calculations of gn for u «*■ 0 and Curve A, Fig* 3
¥111,
31
Calculations of gn for u = 0*07 and Curve B? Fig* 3
....
32
IX. Calculations of gn for u « 0.07 and Curve A, Fig* 3
.**•*.
v
33
1
Chapter I Tm m m TKM
Recently several scsalerapirical theories of nuclear shell structure have been proposed by Feenborg and !£a&iaack,^by !3ordheim,^ and by Mayer.^ Uh© purpose of those shell models is to eaplain the socalled Mmagto»umberw nuclei, containing 2 , 8 , 20 , So, 82, or 126 neutrons or protons# which are particularly stable; & good the
ory should also predict spins, magnetic moments, and other nuclear properties as well.
Consequently, it is of interest to have as
much data as possible concerning the spins, quadrupole moments, and magnetic moments of nuclei in order to test the validity of these theories, and possibly to form bases for improved theories.
It is
the purpose of this investigation to detuiwdne the previously un known magnetic moment of S^» Unclear properties may often be determined by their effects upon the rotational spectrum of a molecule which contains the nucleus in question. The method used in this work was to ex amine the rotational spectrum of the molecule GGS containing the isotope $33* this molecule has an absorption spectrum in tlie neigh borhood of 2h ,000 megacycles per second, and, accordingly, a micro wave spectrometer m s constructed with provisions for applying a magnetic field to the OCS gas. From the Zoeuian effect upon the rotational lines, the nuclear magnetic moment of s3Vas then cal culated.
The following pages contain the theory of the geernan
effect in GCS33, and the method of using it in the determination the magnetic moment of S33 *
3
Chapter II
w m m m wmu&Ticm w oos33 The linear molecule OGS exhibits a rotational spectrum in the region of 2lt,G0Q megacycles per second due to the transik
tion J =•
Since this molecule is a limiting case for symmetric
tops (the moment of inertia about the figureaxis is equal to zero), its rotational spectrum jus of simple structure* Of particular interest here is the spectrum of the isotopic species OCS^«
It was first showh by Townes and GeocJmind^
that the line near 2h»Q20 megacycles has a hyperfine structure which can be explained by attributing a nuclear electric qu&drupole moment to S33, and by giving S^3 a nuclear spin of 3/2* The appear ance of hyperfine structure makes it possible in principle to split the hyperfine components by the application of a magnetic field, and, accordingly* the behavior of the resultant Zeeman pattern is of interest. A* ilyperfins Spectrum of 003^3 The Ilamiltoaian of a molecule having nuclear quadrupole moments can be represented by: H = Hr I Hq where
lip = rotational energy of the free molecule
Hq =? interaction energy between the nuclear quadrupole moments and the molecular electric field. The eigenvalues of I*Ir for a linear molecule are known to he^t
(1 )
J s quantum master for the angular momentum
where
= the effective moment of inertia of the molecule* With the selection rule J J
+1
for absorption spectra# the ro
tational transitions give the frequencies %*J+l =
277X0
O)
•
The effect of the tern Ilj upon the rotational spectrum in the absence of external fields was derived by Fan Fleck, 7 by Coles and Good,^ and by Jauch,^ who adapted the results of Oasimir^ to symmetric—top molecules having one nuclear quadrupole« Hq takes the form: 11q =: A [3(JI) 2 + 3/2(J*I)  I2!2]
(a)
where A=
.eqQ 2i(H3T^353W+5*)
for linear tops
e  electronic charge q = gauss*
Fhe deep valley
labeled A is the bigh«.freqaency Stark component of the F ~ 3/2 3/2 transition, while the one marked B is the Stark component of the F  3/2 1/2 transition*
It will be noticed that the frequency
markers are nonuniform, several of them being either doubled or smeared$ this defect was caused by jerkinoss in the klystron tun ing mechanism, by mechanical vibrations of the tuning motor, and by a small amount of 60cycle frequency modulation* Since the Stark components are modulated 180degrees out of phase with respect to
the undisplaced lines, the phasesensitive detector gives opposite polarities to the Stark and unsplit lines*
23
Chapter I? EB5ULTS AMD O Cm W Sim S A series of recordings of the OCS^ F » 3/2^l/2 absorp
tion line 'Mas made, using different magnetic field strengths#
Of the
eightyseven recordings made, nineteen were selected for analysis, the remainder being rejected became of poor definition of the Zeeman components, erratic frequency markers, o r offscale records* For each record made, there are three independent m y s to calculate
* The separations of the high and the lowfre
quency' components from the aerofield position, and the separation between the two Zeeman components each afford a means of calculation according to Fig* 3 * fable I contains the data to be analysed! in this table the magnetic field is given, together with the fre quencies of the two Zeeman components*
Hie blank spaces in Table I
indicate that some frequencies could not be measured, either because of poor frequency markers, or because of lack of definition in the Zeeman pattern* The data of Table X were transferred to an enlarged drawing of Fig* 3 * and values of
calculated*
This was done
using the three, sets of curves for u «■ 0 , u =• 0*07 , and for u * 0*07, with the hope of obtaining a more consistent set of calculated gylts for one value of u than for the other values* Table IX contains the calculated values for gn using u » 0*07 and curve C of Fig* 3 ! Table XII contains similar calculations
2h
I Frequencies of CCS^ F * 3/2*l/2 Zeeman Components* Esqjerimental Record Bo*
H(kilogauss)
floyf(me.)
f ^ gh(me»)
2M32.62
2USG33.65
1
2.225
2
2.875
3
2.8?5
k
2.875
32.28
— —
5
2.875
— —
33*79
6
hJXLQ
32.15
3U.U3
7
2.225
— —
33.56
8
3.09Q
32.39
33.90
9
3.305
32.1*6
33.98
10
2.725
32.h2
33.7U
n
U.lao
— —
3iu5i
12
2.225
32.61
33*62
13
UJtlO
32.30
31**63
lli
2.010
—
33.66
15
3.090
— —
33*99
16
2.225
*— *■
33.68
17
2.225
32.51*
33*70
18
It.lao
32.37
3W50
X9
2.225
32.62
33.56
32*)4X
33*60 33.96
v.
25 using n ~ 0*07 and curve Bj and. Table 17 contains calculated values of ^
using u «. 0*07 and curve A.
In all of these calculations
the value eqQ * ^29*13 mo*, which best fits our measurements of r .
the hyperfino frequencies, has been used. Values for gn based on u — 0 and u =■ 0.07 have also been calculated.
Tables V, 71, and 711 have been constructed from the
data, using u = 0, and curves C, B, and A* respectively.
Similarly,
Tables VIII and IX contain calculations based on u = 0.07 and curves B and A, respectively* Frobably the most striking feature of the results listed in Tables I — IX is the strong disagreement between the values of based on the lowfrequency Zeeman components, and the values based on the highfrequency lines and the Zeeman component separations! the lowxrequoncy line calculations consistently give much loser values for en than do the other two methods. The reason for this is believe to be as follows s semination of Pig. 6 reveals a Stark component just slightly lower in frequency than the transi tion under study; to what transition this Stark component belongs is not known at this time. As the F — 3/2*l/2 line is split in a magnetic field, the iorfrequency Zeeman component moves rapidly towards the Stark component just mentioned, and, due to the phaseopposition of the Stark component, is cut off on the lowfrequency side.
Mis tends to shift the apex of the lowfrequency line to
a bigger frequency, thereby giving too low a value for gn * Since the Zeeman field also splits the Stark component, the situation is
26
liable II GalouX&tloas of Record No*
b)
for u » 0*0? and Curve C? Fig, 3 2
un
.0n 060
.103
67.28
.0162
*213
9*00
—— — ■

—
.0 23 2
.309
133. 76

« 

.0 3 2 1
.278
8 6 .8 9
1
2*223'
f/eqQ *0083
2
2*073
.0 1 1 ?
3
2*873
 
it
2*873
.0 1 6 1
3
2.873
6
8 .8 1 0
7
2.223
8
3.090
.0 1 2 8
9
3*303
10
2.723
11
8.810
12
2.223
~*oo83
,0063
*111
38.76
13
8 .61Q
.0138
.0220
.191
.36
lit
2.010
—
13
3.090
—
*—
16
2.223
m m
17
.0 2 0 6
x 10
—

—
.0 1 7 2
*213
7*88
.0 1 0 0
.0133
.136
8.81
.0 1 1 3
.0133
.218
10.89
 
 

»
 
_
 
>
—
—

—
—
*—■ —
—
mn.i*>iit

—
2.223
.0072
.0097
.167
3.28
18
8*810
.0130
.0180
.136
8.81
19
2.223
.0083
.0060
.103 .163“
probable error  0.083
—
67.28 39.60
27
liable III Calculations of gn for u « 0*07 and Curve B» Fig* 3 sort! Ho*
H(kHogauss)
n
f/eqQ
^ 2xtO^
1
2*225
.0309
.0319
.51*8
2
2*875
*0292
.03014.
.1*08
125.1*0
3
2*875
.oU5
.0103
.569
10.89
k
2,875
5
2*875
.0357
.0363
.1*82
11*56
6
It*1.00
*0577
.051*1*
.1*71
20.25
7
2.225
*0270
.0291
*5oo
2.60
8
3*090
*0395
*0397
.1*91
6.25
9
3*305
.0622
.OltlB
•H83
10.89
10
2.725
*03lt0
*031*8
.532
2.56
11
It* lo o
*060lt
.0565
.1*90
6.76
12
2.225
.0299
.0310
.532
2.56
13
lt.io .0
.061*5
.0597
.517
1.00
Xb
2*010
*032lt
.0333
.633
136.89
IS
3.090
.0^26
.01*22
.522
.36
16
2.225
.0319
.0329
.565
2i.01
17
2*225
.0326
.0335
.575
36.81
18
k .ItlG
.0601
.0563
*!t88
7.31*
19
2.225
.0278
.0291
.500 .516
2.6 23.19
probable error
—
0*032

>»!*
10. 21*

28
Table 1? Calculations of gn for u ~ 0.0? and Curve A, Fig. 3
1
2.225
.0354
n .0218
2
2*875
.0409
.0253
*336
3
2.8?S

—
... am
2*875
— —
Eocord So.
H(kilogausB)
f/«eqQ
*374
< ?.2xlG^ we 2.56 29.20



 
.049?
*431


.0513
*0323
*4oo
1.00
3.305
♦0522
.0324
*375
2.25
10
2.725
*0453
.0232
.395
.25
11
4.410
* 
■ 

12
2.225
.0347
.0214
.367
5*30
13
4.4io
.0800
.0508
.440
25*00
Hi
2*010
— —
—
IS
3.090
— ■
— —•
16
2*225
1?
2.225
.0393
*0247
.425
12.30
18
4*410
.0731
.0462
.4oo
1.00
19
2.225
.0323
.0199
.342 .390
23.00 10*80
5,
2*8?5
6
4.41Q
7
2.225
8
3*090
9
.0783
16.80
 
probable error — — 0*023
29
Table V Calculations of Record Slo*
H(kilogauss)
for u  0 and. Curve 0, Fig* 3 f/eqQ
n
1
2 .2 2 $
.ool*5
.0063
.109
73.96
a
2*875
.0117
.0170
.226
9.61
3
2.875
 
—
 
k
2.875
—.0161
.021*5
.326
5
2.675
— — •
— —
 «
6
U.iO0
.0337
.292
9U.1Q
7
2.225
—
,
8
3.090
.0121*
.0181
.221*
3.1*1
9
3.305
.0100
.011*3
.166
8.1*1
10
2.725
.0113
.0161*
.230
12.25
XI
kmkxo
——
— —
xa
2.225
—.001*8
.0068
.117
60.81*
13
k.Uio
.0i5h
.0233
*202
.1*9
Hj
2.010
15
3.090
— —
16
2.225
—
17
2.225
.0072
.0100
*172
5.29
18
li.ilX0
.0130
.0190
•li>5
9.00
19
2.225
.00^5
.0063
.109 .195
73.96 1*3.99
.0206
probable error —— 0.01*5

171.60
— ~~
30
HablB TL
Calculations of Eeeord Ho.
H(lcLlogaxtss)
for u » q and Curve B, Fig, 3
f/eqQ
n
%
1
2*225
.0309
.0293
.50)4
13*69
2
2*875
.0292
.0278
.370
9i*.09
3
2*875
•oioS
.0375
J498
9.61
k
2.875
_
— .*
—
5
2.875
.0357
.0330
.1*39
7.81*
6
U.ljio
.0577
.01*92
.1*26
16.81
7
2.225
.0270
.0267
.1*59
.61*
8
3*090
.0395
,0360
.y*5
14.81*
9
3.3QS
.01*22
.0380
.1*39
7.81*
10
2*725
.031*0
.0317
AM
5.29
«G60l*
.0511
.1*1*3
5.76
11
•
12
2.225
.0299
.0281*
.1*88
1*,1*1
13
UO0
.061*5
.0539
.1*6?
0*00
11*
2.0X0
.0321*
.0305
.580
127.69
IS
3*090
.01*26
.0382
.1*73
.36
lo
2.225
.0319
.0300
.515
23.03*
17
2.225
.0326
.0306
.525
33.61*
18
IwUlO
.0601
.0508
.MiQ
7*29
19
2.225
.0278
.0267
.1*59 .1*67
,61* 21.6
probable error
0.031
31
Tab le T O
Calculations of Record $o»
H(kHogauss)
for u = 0 and Curve k 9 Fig* 3 f/eqQ
n
In
(Id)
Using (13)? and applying the condition (Id) to equation (12), some algebraic manipulation gives the result: a
where
**
[?fn w^
Iw i V
+•/F
 1/2 (w^ + £) I*
(16)
w = the imlfwidbh of the unresolved doublet. The data used in calculating gTO consisted of six re
'T5
cordings of the OCS*^ line, three at aero magnetic field, and tliroe for II ■* £,900 gauss.
Both (16) and (16) vrore used.
39 I
o
~ 60 m i
^aax w
l(* » ,65 M3.
san
H = 51900 gauss
w w l«l me,
From (lU): a =■ 0,127 rac. From ( 1 6 ) : a = 0.230
B.
I0 = &7 HBI
Xm x * ^ riM
.53 me.
II * 5,900
w =■ .70 me,
From (lli): a = 0.12a From (16) i
a = 0.135 C.
I = 69.3 mn, o
^ = .52 MC:.
^
 52 >” w = .77 me.
H ■» 5,900
From (la): a  0.151 From (16): a — 0.152 Tuo average of tee six values of a given above is: a ~ 0.157 me. © 5,900 gauss, Using this value for a , the result for g is: “ 0«l57(me») x 1.312$(kilogauss/iy._) 5.9 (kilogauss)
 — 0.035 nuclear units. lo This result compares very well with that of Coles u, who obtained the value 0.036, and not quite so well with the result of 15 Jen , who obtained 0.026.
ko
BIBUOGRAPHT X.
Eugene Feenberg and Kenyon 0* Hammck, Phye. Rev. 7$, 1877(49)
2.
L. W. lk>ixlheim, Phys. Rev, 73, 1694 (49)
3* Stela Gooppert Mayer, Fhym, Key# 73, 16 (90) Phys. Rev. 78, 1969 (2$) 4. T. W* Bakin, W. E. Good, and D. K. Doles, Phys. lev. 70,360(46) A* Roberts, Fhy3 . Rev* 73, 1403 (1*8) 3*
G. H. Tovmes and S. Geechwind, Bays* Rev. 74, 626 (ho)
6m
Z. I. Slawsky and B. M. Etennison, J* Ch©su Phys. 7, 309 (39)
7.
J. H. Van Vleck, Phys. Rev. 71, 468 (4?)
8.
D. &* Doles and W* E* Good, Phys* Rev. 70, 979 (46)
9.
J. M. Jauch, Phys. Rev. 72, 713 (47)
10.
H. B. G. Oasindr, B