| Re: Some question about small cluster calculations ( No.1 )|
- Date: 2012/08/28 21:15
- Name: T.Ozaki
> 1- How to optimize the cluster for which triplet is the
> ground state or some other state with higher multiplicity
> is the ground state.How to achieve this goal with OPENMX.
> As for as I know there is no keyword to define the multiplicity
> in OPENMX.
OpenMX does not support calculations with a fixed multiplicity of
total spin moment, but supports a way which determines a magnetic state
during SCF iteration starting from the initial spin configuration.
> 2- How to obtain the band structure of the small cluster, because
> for this one should require the crystal structure, which is not
> available for the cluster. Should I use the cell size generated by OPENMX
> as the cell specification in input file.
For cluster systems, there is no band dispersion, and the energy spectrum is
given by the sum of delta functions.
> 3- How to obtain the magnetic properties of these cluster.
Many papers have already addressed the issue using OpenMX.
Please look those papers.
> How to define Hubbard value.
The Hubbard U used in the DFT+U method of OpenMX is an adjustable parameter
more or less, and OpenMX does not have a functionality to calculate the Hubbard U
based on first-principle methods such as constraint scheme.