CASTEP > Tasks in CASTEP > Setting up CASTEP calculations > Requesting electronic, structural, and vibrational properties > Requesting population analysis

Requesting population analysis

Performing population analysis produces Mulliken charges, Mulliken magnetic moments, Mulliken partial charges for each angular momentum component, Mulliken bond populations (charge and spin), and Hirshfeld charges. You can use the Distance cutoff for bond populations option on the Properties tab to limit the amount of output from the bond population analysis. You can also use the Calculate band populations option to calculate the band contributions to the Mulliken charges, so that the results can be used to generate a PDOS chart.

The Population analysis checkbox on the Properties tab of the CASTEP Calculation dialog is checked by default.

It is not possible to specify the number of atomic orbitals to be used in the population analysis explicitly in the CASTEP interface. If the spilling parameter reported in the .castep output file is too large (more than 5%), it may be that the default CASTEP parameters were insufficient for this calculation. In such circumstances you should edit the .cell file and change the SPECIES_LCAO_STATES parameters for atomic species, then run the input files again. The SPECIES_LCAO_STATES parameter for a species should be set such that it results in a complete set of angular momentum states. For example, to use a single s and single p state SPECIES_LCAO_STATES must be 2.

To perform population analysis

  1. Choose Modules | CASTEP | Calculation from the Materials Studio menu bar.
  2. Select the Properties tab.
  3. Ensure that the Population analysis option on the properties list is checked.
  4. Optionally, modify the Distance cutoff for bond populations field to include more or less atomic pairs in the calculation.
  5. If you wish to generate partial and local densities of states for the valence band, check the Calculate band populations option.
See Also:

Mulliken population analysis
Hirshfeld charge analysis
Phonon density of states
Density of states and partial density of states
Optical properties
CASTEP Calculation dialog

Accelrys Materials Studio 8.0 Help: Wednesday, December 17, 2014
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