Default MO Guess
Superposition of atomic densities - default
- Performs atomic SCF on each atom
- Spherically averages occupations
- Nearly always the best guess
When does atomic guess fail?
- Some ECPs
- Many calculations on metals, especially open d/f shells
- Diffuse basis sets
- Some DFT calculations
Other Approaches
- Use eigenvectors from a related calculation
- Restore from the same or previous Dumpfile (GETQ directive)
- vectors stored in default sections, or in response to section specified on ENTER