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Title of Thesis

Ishaq Ahmad
Institute/University/Department Details
Department of Physics/ Quaid-i-Azam University, Islamabad
Number of Pages
Keywords (Extracted from title, table of contents and abstract of thesis)
magneto optical absorption, synchrotron radiation, calcium, cadmium, paramagnetic effect, diamagnetic effect, magneto-optical patterns, quasi-landau resonances

The magneto-optical absorption spectroscopy experiments on calcium and cadmium are presented. The experimental setup and the method of analysis is described. The data were acquired utilizing the linearly polarized light emitted by the 2.5 G eV electron accelerator, a 6 Tesla superconducting magnet, and a 3-meter high dispersion spectrograph with the photographic detection.

The design and construction of a new high temperature furnace is described. It is a specially designed resistance furnace (king type), capable of working up to 2000 °C and fits in the restricted warm bore of ~ 10 cm of the superconducting magnet.

The magneto-optical absorption spectra of calcium were recorded in the wavelength range from 2020 A to 2090 A. Measurements of oscillator strengths (relative f-value) for the principal series of calcium

3p6 4s2 1 s0 †’ 3p6 4snp 1p1

are reported. A quantum defect plot of the density of oscillator strengths of discrete transitions in calcium yields the photoionization cross section at the threshold as 2.04 ± 0.20 Mb, in agreement with earlier measurements.

In case of cadmium, the magneto-optical absorption spectra were recorded in the wavelength range from 1370 A to 1480 A. The oscillator strengths for transitions

4d10 5s2 1 s0 †’ 5snp 1p1 (8 ‰ n ‰ 13)

have been measured. The value of the total photoionization cross section at the ionization threshold of cadmium is found to be 4 ± 2 Mb. In addition, quasi-Landau resonances in cadmium spectrum are observed for the first time. The separation between these resonances around ionization threshold is found to be 1.5 hwc, where wc is the cyclotron frequency. This value of the resonance separation agree with that. observed in other alkaline earth elements.

Download Full Thesis
12028.85 KB
S. No. Chapter Title of the Chapters Page Size (KB)
1 0 Contents 0
1755.52 KB
2 1 Introduction 1
1214.73 KB
  1.1 Atoms in Uniform Magnetic Fields 5
  1.2 The Hamiltonian 6
  1.3 The Paramagnetic Effect 7
  1.4 The Diamagnetic Effect 12
3 2 Magneto-Optical Spectroscopy 16
917.69 KB
  2.1 The Circular Dichroism and Birefringence 16
  2.2 The Complex Magneto-Optical Angle 18
  2.3 The Intensity Formula 19
  2.4 The Magneto-Optical Patterns 20
  2.5 Fitting of the Experimental Line Profiles 21
4 3 Experimental Procedure24
1401.57 KB
  3.1 The Synchrotron Radiation 25
  3.2 The Magnet 28
  3.3 The Absorption Cell 30
  3.4 The 3M Vacuum Spectrograph 32
5 4 The High Temperature Furnace 35
755.93 KB
  4.1 Design and Construction 35
  4.2 The Design of the Heating Element 37
  4.3 The Power Supply and the Radiation Shielding 38
  4.4 First Test 39
  4.5 Selection of Metal/Ceramic Combination 39
  4.6 Final Test 39
6 5 The Calcium Spectra 41
1140.59 KB
  5.1 Introduction 41
  5.2 Results and Discussion 42
7 6 The Cadmium Spectra 50
1351.57 KB
  6.1 Introduction 50
  6.2 Results and discussion 51
  6.3 Quasi-Landau Resonances 55
8 7 Summary and Suggestions for Future Work 63
3613.46 KB
  7.1 Summary 63
  7.2 Suggestions for Future Work 64