Lecture Topics for PHYS 475
- Jan. 4, 2011
- Discussion of Course Outline
- Evidence for Atoms (conjecture by Greeks, kinetic molecular
theory, Brownian motion, direct observation)
- Electrons as a fundamental part of atomic structure
(electrolysis)
- Electromagnetic nature of atomic structure
- Jan. 5, 2011
- Further early atomic investigations
- Thomson's e/m, cathode ray experiments
- Millikan oil drop to measure quantized charges
- Rutherford's evidence for a nuclear atom
- Failure of a classical atomic model
- Spectroscopic observations (classroom demonstration)
- Distinct emission lines of electrical discharge through
atomic gases
- Uniqueness of lines
- Colour/Energy Bands in molecular gases
- Fluorescent lights: bands with lines
- Incandescence: black body spectrum
- Absorption lines in the solar spectrum
- Explanations of spectral lines
- Rydberg-Ritz formula for hydrogen and one-electron atoms
- Wavenumber and the Ritz combination principle
- Classical EM: oscillating electrons like musical notes?
- Difficulties measuring IR and UV lines
- Jan. 7
- The Bohr Model
- Quantized photons
- Circular orbits and planetary model
- Quantised angular momentum
- Quantised radii and energy
- Common units
- Explanation of the Rydberg-Ritz formula
- Isotope shift and higher Z
single-electron atoms/ions
- Jan. 11
- Relativistic corrections to the Bohr model
- Suggestion by Sommerfeld that ellipitical orbits with
identical L and gross E are possible
- Relativistic corrections are related to (v/c)2
- Percentage energy shift related to (a/n)2
- For hydrogen fine structure of 1 cm-1
- Moseley's measurement of characteristic X-rays
- Square-root of frequency related to atomic number; first
measurement of Z
- Can explain roughly linear
behaviour by using shell-Bohr model with shielding factors
- Convenience of thinking of holes dropping from K-shell to L
and M shells
- Increase of fine structure energies for higher Z
- Jan. 12
- Radiative decay
- Use of classical electric dipole radiation formula
- Decay times that are several million times the period of
oscillation
- Gives good estimates if the transition is not-disallowed by
selection rules (we'll see those later)
- Einstein coefficients
- Two-level atom with degeneracy interacting with radiation
- A rate equation involving absorption, stimulated emission,
and spontaneous emission.
- Using thermal equilibrium and Boltzmann statistics to
establish relations between A
and B coefficients
- Jan. 14
- Zeeman effect
- Relative scale 10 GHz or 1 part in 5000
- A classical 3-D harmonic oscillator with a Lorentz force
perturbation
- The Larmor frequency WL
- Larmor frequency gives matrix-cross terms which give new,
shifted eigenfrequencies
- Oscillation along z-axis
is
unaffected;
the
p-line
- Jan. 18
- Zeeman effect cont'd
- New circular eigenmodes with shifted frequences the s+ and s- lines
- Polarizations when viewing transverse and longitudinally to
the magnetic field
- Chapter 2: Quantum mechanical treatment of H-atom
- Using spatial rep for Hamiltonian
- Relative coordinates and reduced masses implied
- Jan. 19
- Quantum mechanical treatment of H-atom cont'd
- Separation of r and
angular
coordinates
in
the
Laplacian
and
in
y
- Angular momentum in the Laplacian
- Separation of q and f coordinates
- Eigenfunctions and
eigenvalues of F(f)
- Using ladder
operators to generate new Yb
- Commutators of ladder operators
- Jan. 21
- The Ylm functions
- Finding the form for
the m=mmax=l Y-function
- Establishing the
value for b
- Generating the Ylm functions
- Cartesian forms of Ylm
- Angular distributions
- Jan. 25
- Solving the radial
equation
- Transforming to P=rR function
- Looking at P as the solution to 1-D
Schrodinger equation
- Transforming to
dimensionless distance r and
potential energy l
- Quantisation/eigenvalue
condition
imposed
on l
- The quantum
mechanical derivation of the Bohr formula
- Some expectation
values and wavefunctions
- Jan. 26
- Transitions between
states in H
- Elements of
time-dependent perturbation theory: Fermi's Golden Rule
- The electric dipole
approximation for the electromagnetic field
- The perturbing
Hamiltonian
- Splitting of the
matrix element into radial and angular integrals
- Jan. 28
- What does ȓ do as an
operator? Answer: creates more spherical harmonics
- Using a basis set of
"spherical" vectors since they have simple operation properties
- Selection rule Dm=0
for
Ap type radiation
- Feb. 2
- Summary of m selection rules
- Dl=±1
- Argument based on
spherical harmonic identity
- Argument based on
parity operator
- Relativistic
corrections
- Electron spin/ spin
operator algebra
- Feb. 4
- Origin of spin-orbit
interaction
- The Bohr magneton
- Using conventional
operators to describe the perturbing Hamiltonian
- Expression for the
spin-orbit energy shift
- Trying to find
eigenstates of j in order to
determine s·l
- Feb. 8
- Slight review of the
spin-orbit splitting, similarity to earlier estimates
- Using the old
eigenstates to construct new eigenstates that are eigenstates of new
Hamiltonian but not lz and sz
- Clebsch-Gordan
coefficents
- Labelling states
with the LS coupling scheme
- Degeneracy of 2s 2S1/2
and 2p 2P1/2 even after relativistic corrections
- Feb. 11
- Lamb shift
- Difficultly of
resolving fine structure of Ha line because of Doppler broadening
- Lamb-Retherford
experiment in 1947
- Metastable 2s 2S1/2
state
- RF cavity and Zeeman
shift
- Quantum
electrodynamics to calculate 2s 2S1/2
and 2p 2P1/2 1059 MHz splitting
- Feb. 15
- Helium
- Non-interacting
ground state
- Calculation of
repulusion perturbation for ground state
- Variational approach
gives slightly better results
- Excited states of
helium
- Feb. 16
- Degenerate
pertubation theory
- J-K matrix and
solving for eigenvalues and eigenvectors
- Direct and exchange
energies
- Feb. 18
- n.b. the linear
combinations are eigenstates to 1st order only
- Behaviour of J and K
if we separate out 1/r12
- Spin states
associated with ySspace and yAspace
- "Spin Dependent"
splitting of 1L and 3L states
- Convergence to
hydrogen energy levels
- March 1
- Labelling of energy
levels
- Assigning spectral
lines to transitions
- Possibility of using
new 'J'
- Ground state J
integral 34 eV using "enclosed charge" method
- March 2
- J and K integrals
for excited states
- Separation into
spatial and angular parts
- Expressing 1/r12 in
terms of spherical harmonics
- March 4
- Brief review of some
concepts from Chapter 3
- Chapter 4: Alkalis
- Shell structure
- Using Bohr model for
excited states
- The "ell" dependent
quantum defect
- March 15
- Using a central
potential to account for electrostatic repulsion
- Separation of
equation
- Transformation to
radial equation
- Numerical solution
of radial equation
- March 16
- Slater determinant
- A more QM approach
to J=L+S
- Fine structure in alkalis and the Lande formula
- Relationship of spin-orbit coupling to 1/r3
expectation value
- March 18
- Scaling in the Lande
formula
- Relative intensities
from fine-structure splitting
- Numerical solution
to Schrodingers radial equation (Exercise 4.10)
- March 22
- Using Matlab to work
through 4.10
- Energy resolution
- Using nodes to label
the levels
- Modification to Zeff
- Difference for
different ell values
- Using solutions to
find new potentials
- March 23
- Russell-Saunders or LS coupling scheme
- Residual
electrostatic interaction to account for exchange
- Total L and total S as good quantum numbers
- Terms
- Equivalent electrons
and Hund's rules
- March 25
- Fine-structure in LS coupling and projection rule
- Interval rule for
fine-structure
- Possibility of a jj coupling for heavy atoms
- March 29
- Configurations,
terms, levels, and states
- Selection rules for LS coupling scheme
- Violation for jj coupling scheme:
intercombination lines in large Z
systems
- Zeeman effect
- Lande g-factor
- Multiple lines for
anomalous Zeeman effect
- April 1
- Hyperfine structure
- Fermi contact
interaction
- IJ coupling to give F
- Hyperfine splitting of hydrogen 1.42 GHz
- Hydrogen maser
- April 1
- Extension to ell not equal to 0 states
- Z dependence of HFS
- Interval rule for
HFS and assigning quantum numbers
- Isotope shift
- Volume effect
- April 5
- HFS and the Zeeman
effect
- Weak field with IJ coupling
- Strong field when J precesses around B
- Intermediate
field region with no crossing
- April 6
- Measuring hyperfine
structure
- Fabry-Perot when HFS
exceeds Doppler effect
- Doppler-free laser
spectroscopy
- NMR, chemical shift
- Atomic beam (double
Stern-Gerlach) technique
- Atomic clocks based
on hyperfine structure