Atomic Orbitals

AOLoewdin
Section: Atomic Orbitals
Type: logical
Default: no

This option determines if the atomic orbital basis is orthogonalized or not. This is done for using the Loewdin orthogonalization scheme. The default is set to no for the moment as this option is not yet implemented for isolated systems, and seems to lead to important egg-box effect

AONormalize
Section: Atomic Orbitals
Type: logical
Default: yes

If set to yes, Octopus will normalize the atomic orbitals individually. This variable is ignored is AOLoewdin<\tt> is set to yes.

AOSubmesh Section: Atomic Orbitals Type: logical If set to yes, Octopus will use submeshes to internally store the orbitals with their phase instead of storing them on the mesh. This is usually slower for small periodic systems, but becomes advantageous for large supercells. Submeshes are not compatible with Loewdin orthogonalization. For periodic systems, the default is set to ye, whereas it is set to no for isolated systems. AOThreshold Section: Atomic Orbitals Type: float Default: 0.01 Determines the threshold used to compute the radius of the atomic orbitals for LDA+U and for Wannier90. This radius is computed by making sure that the absolute value of the radial part of the atomic orbital is below the specified threshold. This value should be converged to be sure that results do not depend on this value. However increasing this value increases the number of grid points covered by the orbitals and directly affect performances. AOTruncation Section: Atomic Orbitals Type: flag Default: ao_full This option determines how Octopus will truncate the orbitals used for LDA+U. Except for the full method, the other options are only there to get a quick idea. Options: ao_full: The full size of the orbitals used. The radius is controled by variable AOThreshold. ao_box: The radius of the orbitals are restricted to the size of the simulation box. This reduces the number of points used to discretize the orbitals. This is mostly a debug option, and one should be aware that changing the size of the simulation box will affect the result of the calculation. It is recommended to use ao_nlradius instead. ao_nlradius: The radius of the orbitals are restricted to the radius of the non-local part of the pseudopotential of the corresponding atom.