Section- I: Atomic Spectra 1. Bohr's Theory ans Spectrum of Hydrogen Atom 2. Sommerfeld Theory of Hydrogen Atom 3. Vector Atom Model and Stern- Gerlach Experiment 4. Quantum Mechanical Theory of Hydrogen Atom 5. Pauli Exclusion Principle and Atomic Structure 6. Spectra of Alkali and Alkaline Elements 7. Fine and Hyperfine Structure of Spectral Lines 8. Complex Spectra 9. Effect of Magnetic and Electric Fields on the Spectrum of an Atom Section II: X-Rays and X-Ray Spectra 1. X-Ray and X-ray Spectra Section III: Molecular Binding 1. Molecular Binding Section- IV: Molecular Spectra 1. Introduction 2. Microwave of Far Infra Red Spectroscopy 3. Near Infra- Red Spectroscopy 4. Raman Spectra 5. Electronic Spectra 6. Molecular Electronic States: Symmetry Properties of Rotational Levels, Nuclear Spin ans Intensity Alternation 7. Spin Resonance Spectroscopy Section- V: Laser Physics 1. Laser Physics 2. Masers and Lasers 3, Non Linear Optics 4. Applications of Lasers