EFFECT OF SOLID DILUTION ON THE CRYSTAL FIaD SPEC OF COBALT AND NICKEL DOUBLE SULPHATES
SINGLE CRYSTALS
Thesis submitted to Indian Irstithte og Technology, Delhi for partial fafilmert of the Degree of Doctor of Philosophy
august,
1976CERTIFI GATE
This is to certify that the thesis entitled
"Effect of Solid Dilution on the Crystal Field Spectra of Cobalt and Nickel Double Sulphates Single Crystals"
being submitted 'by Shri Rajbir Singh Daryan to the Indian Institute of Technology, Delhi, for the award of the Degree of Doctor of Philosophy in Physics is a record of bonafide research work carried out by
Mr. Daryan has worked under my guidance and supervision and has fulfilled the requirements for the submission of this thesis.
The results contained in this thesis have not been submitted in part or full, to any other University or Institute for the award of any degree or diploma.
( S.C. i4athur Thes s Supervisor.
ACKNOV
rT
The author wishes to expres his deep sense of gra- ti ude to Dr. S.C.Mathur for his valuable guidance and dis- cussion failing which the present work would have been impossible. I should also like to th Dr. G.Basu, for many helpful discussions and help in computer programming for analysing spectral bands. The keen interest of Prof.
M.S.Sodha, Dr. D.P.Tiwari and Dr. K.Singh in the work is also acknowledged. Prof. K.L.Chopral Prof. C.L.Mehta and Prof. A.K.Ghatak as the successive Chairmen of the Depart
-
ment have been very generous in providing the necessary facilities for completing this work and I am greatly in- debted to them for the s
It is a pleasure to acknowledge the cooperation received from all the members of the faculty and members of non-teaching staff of the Physics Department, my colleagues Dr. B.Kumar, Dr. D.C.Singh, Dr. D.P.S.Malik, Dr. M.S.Temar, Messers Jagpal Singh, A.K.Gupta, 1414.Singhal, and S.Mitra have provided valuable help at various stages of the work and I wish to take this opportunity to thank them
There yet others who have indirectly helped me and I would fail in my duty if I do not express my sense of gratefulness to them particularly Dr. Anand Swaroop and. Mr. Jitendra Singh.
The authors t so go to Mr ukla and
Mr. N. .Gupta for executing the task of typing the manuscript
and tracing the fi res with great care and thoroughness respectively.
The award of a Junior Research Fellowship by C.S.I.R. is gratefully acknowledged.
And lastly I should mention my wife, Curesh Daryant who has all these years been a silent sufferer of my
academic adventures,
(R.
MENTAL
Preparation of Specimen 39
Recording of the spectra 40
g2glIrgi gtiPatil 6
Spectrophotometer * • * 41
Operatton
48
CONTENTS
ODUCION AND GEN! 01,6' 1
THEORETICAL * 12
i) Absorption Spectra in solids .. 12
Old Theories 12
Quant t; theory
ii) Crystalline Ele 16 Theory
iii) Formation 9f cluster about the metal Ions of the iron 23 group
iv) Nature of transitions ... 26 Electric dipole radiation ... 28
Quad pole radiation .. 28 Magnetic dipole radiatidh ... 29 Electric dipole radiation due
to tht # stortion by crysta
lline electric fields ... 29
v) Band Width
... 31
vi) Intensity of spectral trans-
itions .. .
33
The Einsten absorption add
Emission coefficients ... 33 Dipole and Oscillator strength.. 3)4-
es
• 0 SO
• * O a 0
O ø
•
O *
• * • O 0
0
O 0•
• 10.
(e) Experimental procedure (f) Chemical analysis
4. RESULTS
DISCUSSION OF Taal Rio LT i) Introduction
ii) Nickel Ion
Optical Absorption spectra Oscillator Strength
Crystal structure
Crystal field and energy level Crystal field parameters
(i) Cubic Field parameter
(ii Tetragonal field parameter (iii)Term separation
(iv) Magnetic moment (v) Splitting factor, g
(vi)Magnetic anisotropic K iii) Cobalt Ion
Optical Absorption Spectra S 00etry of the ery tal field ano energy level
51 54 61-73 74-128 7
77 1 1 77 83 86 86 93 93 9 io 9 10i 112-128 112
. 0 0 116 Cystal field parameters 0 OP
I. 118
i Cubqc fteld parameter .. . 118 ii) Tetragonal Field parameters ... 121 ii )Term separation, Et 4. 0 122 iv) Splitting factor, g 0. 0 123
