Databases

CRC Handbook of Chemistry and Physics
www.hbcpnetbase.com/
Data may be accessed after purchasing a personal or institutional subscription.

NIST Ground Levels and Ionization Energies for Neutral Atoms
http://physics.nist.gov/PhysRefData/IonEnergy/ionEnergy.html
Compilation of the currently accepted values of ground state and ionization energies of neutral atoms. These data inform semi-empirical atomic and molecular orbital calculations.

WebElements Periodic Table of the Elements
www.webelements.com/webelements/scholar/index.html
Interactive periodic table of the elements, with extensive tabulation of physical and chemical properties.

Tutorials

A useful collection of resources covering many areas
www.ias.ac.in/initiat/sci_ed/resources/chemistry/physical.html
Useful links from the Indian Academy of Sciences.

Hydrogenic Atoms
http://webphysics.davidson.edu/faculty/dmb/Hydrogenic/outline.html
Living graph of hydrogenic atom wave functions.

The Electronic Structure of Higher Atoms
www.mona.uwi.edu/chemistry/Courses/C10J/documents/lecture%205%20-%20electronic%20structure%20of%20higher%20atoms.pdf
Applies the orbital approximation to helium.

Hartree Fock Method
www.chm.davidson.edu/ronutt/che401/HartreeFock/HartreeFock.htm
Example of Hartree Fock method (or self consistent field).

Rydberg Atoms and the Quantum Defect
www.phy.davidson.edu/StuHome/jimn/Final/Pages/FinalRydberg.htm
Quantum defects.

Selection Rules
http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/hydazi.html#c3
Summary of the selection rules.

The Assignment of Atomic Term Symbols
www.chem.ufl.edu/~itl/4412/lectures/ATermSym.html
Step-by-step help for assigning term symbols.

Spin Orbit Coupling and Atomic State (Term) Symbols
www.trentu.ca/chemistry/documents/termsymbols.pdf
A very 'wordy' explanation on spin-orbit coupling.

What is a singlet, doublet, triplet etc state?
www.madsci.org/posts/archives/mar2001/985185599.Ph.r.html
Singlet, doublet, and triplet explained using quantum mechanical notation (operators etc.)

Atomic Absorption and Emission Spectra
http://csep10.phys.utk.edu/astr162/lect/light/absorption.html
A simple introduction to atomic absorption and emission spectra.