Atomic Moclecular and Laser Physics 2010

Atomic, Molecular and Laser Physics

Instructor: Dr. [Sabieh Anwar] Office hours: Tuesday, Thursday (5-6 pm)

Teaching Assistant: [Shahid Sattar] Office hours: Tuesday, Thursday (4-6 pm)

Textbook: Molecular Quantum Mechanics, Fourth edition by Peter Atkins, Ronald Friedman

Course outline: Click here

Week 1 Spins in magnetic fields

• Zeeman and singlet-triplet bases and their inter-conversion
• Spin in an external magnetic field, magnetogyric ratio
• Zeeman Hamiltonian
• Bloch sphere and evolution of states on the sphere

Week 2 Spins in magnetic fields (continued)

• Rotation operators, viewing a propagator as a rotation operator
• evolution of observables
• rotating wave approximation
• NMR and ESR spectra

Week 3 Transitions between energy levels

• Time-dependent perturbation theory basics: constant, exponentially increasing and oscillatory Hamiltonians
• Approximate and exact formulas
• Rabi flopping
• rotating wave approximation revisited
• Comparison between constant and oscillatory Hamiltonians

Week 4 Interaction of electric dipoles with Radiation

Spontaneously modulated spin textures in a dipolar spinor Bose-Einstein condensate (photograph by UC Berkley)

A laser-microscalpel which makes possible to target one cancer cell at a time. The inset demonstrates where the laser severs the axon(photograph by H. Cinar and Y. Jin)

• Transitions to continuum states
• Fermi golden rule
• Electric dipole interacting with an electromagnetic wave
• Absorption, stimulated and spontaneous emission
• Interaction with thermal radiation
• Einstein's A and B coefficients

Week 5 Lifetimes of states

• Natural broadening
• Pressure broadening
• Doppler broadening
• Lorentzian and Gaussian lineshapes, lineshape function, homogeneous and heterogeneous broadening
• What about lineshapes in solids?
• Emission rates for a quantum harmonic oscillator and comparison with a classic accelerating electric dipole

Week 6 Selection rules

• Selection rules for the magnetic quantum number

Week 7 Selection rules (contd.)

• Selection rules for the orbital quantum number
• Laporte rule: electric dipole transitions are allowed between opposite parity states
• Examples of applications of selection rules
• Grotrian diagram
• Metastable states and phosphorescence
• Angular momentum and helicity of the photon: Review article for self-study: A justification of selection rules Spectroscopic selection rules: The role of photon states (J. Chem. Ed., Vol. 76 No. 9, 1999)

Week 7 and 8 Atomic Spectrum of hydrogen: fine structure

• Fine structure: relativistic correction
• Fine: structure: spin-orbit interaction: Review articles for self-study: On the classical analysis of spin-orbit coupling in hydrogenlike atoms (Am. J. Phys. 78 (4), 2010) The Thomas precision factor in spin-orbit interaction (Am. J. Phys. 72 (1), 2004)
• Good quantum numbers
• The quantum number j and fine structure of the energy levels
• Fine structure of the H spectrum, multiplets in the Lyman and Balmer series
• Lamb shift and Lamb's experiment Review article for self-study: Stern-Gerlach Experiment How a bad Cigar helped Reorient Atomic Physics

This image shows the mapping of Milky way at different wavelengths.

Week 9 Zeeman and hyperfine effects

• The Zeeman effect: weak and strong fields
• Effect on the spectrum by placing the atom in external magnetic field
• Hyperfine interaction
• The 21 cm line and some of its uses in radio-astronomy
• The F quantum number

Week 10 Multi-electron atoms (before the spin-orbit interaction)

• Pauli's exclusion principle, fermions and bosons
• Why does the singlet electron state has a higher energy than the triplet electron state?
• Effect of Coulombic repulsion on He levels: ground and first excited state
• Hartree's theory and its important results
• Concept of effective nuclear charge

Bose-Einstein condensation at 400, 200 and 50 nK. A very dense blob formed at the center is representing the condensate.

Week 11 The Periodic Table

• The Periodic Table and ground state electronic configurations
• Electronic configurations and anomalies
• Why does energy depend on l?
• Trends in the periodic table explicable from Hartree's calculations
• Guest lecture by Rafiullah: Bose-Einstein condensation

Review article for self-study: Bose-Einstein condensation (Source: Physicsworld.com)
Observation of Bose-Einstein Condensation in a Dilute Atomic Vapor (Science, Vol 269, 1995)

Week 12 Spectroscopy of Multi-electron Atoms

• Electronic configurations, terms, levels and states
• Hund's rules
• Examples of atomic spectra: helium, alkali metals (lithium, sodium etc), alkaline earth (calcium etc)
• Atomic absorption spectroscopy
• X-ray spectroscopy
• Photoelectron spectroscopy: X-ray Fluorescence and Auger electron spectroscopy
• Zeeman effect in multi-electron systems

Week 13 Lasers

• Review of spontaneous emission, stimulated emission and absorption
• Population inversion and conditions for laser operation
• Gain of the laser medium, laser as an amplifier
• laser as an oscillator
• Single and multi mode operation
• Pulsed mode operation: Q-switching and mode-locking
• Characteristics of laser light
• Some example lasers: He-Ne, excimer, Nd:YAG and diode lasers