Possible Results of an SCF Procedure

In an SCF calculation, the energies from one iteration to the next can follow 

After a number of iterations, the energy from one iteration may be the same as from the previous iteration. This is what chemists desire a converged solution. 

The energies from one iteration to the next may oscillate between two values, four values, or any other power of 2. (The author is not aware of any examples other than powers of 2.) 

The values could be almost repeating but not quite so. In chaos theory, these are called Lorenz attractor systems. 

The energies may be random within some fixed range. Random-number generators use this property intentionally. 

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