Self-Consistent Field (SCF)

The SCF procedure is the iterative process where Siesta solves the Kohn-Sham equations. An initial guess for the electron density is used to calculate a potential, which is then used to find a new density, and this loop continues until the density and total energy are stable (self-consistent).

• MaxSCFIterations: The maximum number of iterations allowed before the calculation stops.
• Mixer Method: The algorithm used to mix the density from previous iterations to generate the guess for the next. 'Pulay' is a robust and commonly used default.
• Mixer Weight: Controls how much of the new density is mixed with the old. A smaller value can improve stability for difficult-to-converge systems but may slow down convergence.
• DM Tolerance: The convergence threshold based on the change in the density matrix between iterations. This is often the most reliable convergence criterion.