Molecular Hamiltonian (open boundary conditions)

Keyword: MOLECULE

Description: A molecule with open boundary conditions.

Required keywords

Keyword Type Description
NSPIN section Two integers, the first the number of spin up electrons and the second the number of spin down.
ATOM section Add an atom to the system. The format of the section is label charge COOR x y z . For example, a Lithium atom with atomic charge 3 at (.5, 0, -.5) would be ATOM { Li 3 COOR .5 0 -.5 }.

Optional keywords

None



Periodic Hamiltonian

Keyword: PERIODIC

Description: A bulk material simulated with periodic or twisted boundary conditions.

Required keywords

Keyword Type Description
NSPIN section Two integers, the first the number of spin up electrons and the second the number of spin down.
ATOM section Add an atom to the system. The format of the section is label charge COOR x y z . For example, a Lithium atom with atomic charge 3 at (.5, 0, -.5) would be ATOM { Li 3 COOR .5 0 -.5 }.
LATTICEVEC section Enforce the periodic boundary conditions as a parallelepiped, with three vectors specifying the edges. For example, a cubic cell with sides 1.0 a.u. is:
LATTICEVEC { 1.0 0.0 0.0 0.0 1.0 0.0 0.0 0.0 1.0 }

Optional keywords

Keyword Type Default Description
KPOINT section {'0 0 0': None} Specify the k-point (i.e., boundary conditions) at which the trial wave function is constructed. For instance, 0 selects periodic and 1 selects anti-periodic boundary condition along the corresponding lattice vector.
CUTOFF_DIVIDER Float 1.0 Control how many unit cells to generate ghost centers around the simulation cell. 1 is one unit cell, 2 is one half a unit cell, and .5 is 2 unit cells. This will often be set correctly by the conversion program.
EWALD_GMAX integer 200 How far to search to generate the k-mesh for the Ewald summation. Only the vectors with significant weights are kept. If you have a cell with a lattice vector larger than around 300 Bohr, this may need to be increased.


Pseudopotential

Keyword: PSEUDO

Description: Use an effective nonlocal potential to remove the core electrons from the system. This is handled more or less as described in Mitas, Shirley, Ceperly, J. Chem. Phys. 95, 3467 (1991). The first word in the pseudopotential section must be the label of the atom to which is corresponds.

Required keywords

Keyword Type Description
BASIS section Input for a Basis function for the radial part of the pseudopotential.

Optional keywords

Keyword Type Default Description
AIP integer 6 Number of atomic integration points. Available are Gaussian rules with 4, 6, 12, 18, 26 and 32 points.
ADD_ZEFF Flag False Add the effective charge while in range of the pseudopotential, for soft psp's that have the effective charge included.