DIPOL: Difference between revisions
(Created page with '{{TAGDEF|DIPOL|[real array]|{{FIXME|default none or the origin 0 0 0}}|(VASP.3.2 only)}} For VASP.4.X behavior please refer to [[Monopole_Dipole_and_Quadrupole_corrections|Monop…') |
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{{TAGDEF|DIPOL|[real array]|{{FIXME|default none or the origin 0 0 0}}| | (VASP.3.2 only)<br /> | ||
{{TAGDEF|DIPOL|[real array]|{{FIXME|default none or the origin 0 0 0}}|}} | |||
For VASP.4.X behavior please refer to [[Monopole_Dipole_and_Quadrupole_corrections|Monopole, Dipole and Quadrupole corrections]]. | For VASP.4.X behavior please refer to [[Monopole_Dipole_and_Quadrupole_corrections|Monopole, Dipole and Quadrupole corrections]]. | ||
It is possible to calculate the total dipole-moment in the cell, using the option | It is possible to calculate the total dipole-moment in the cell, using the option | ||
{{TAG|DIPOL}}=< | {{TAG|DIPOL}}='''R'''<sub>x</sub> '''R'''<sub>y</sub> '''R'''<sub>z</sub> | ||
where '''R'''<sub>x</sub>, '''R'''<sub>y</sub> and '''R'''<sub>z</sub> specify the center of the cell in direct lattice coordinates. | |||
---- | ---- | ||
Mind: the calculation of the dipole requires a definition of the center of the cell, and results might differ for different positions. | Mind: the calculation of the dipole requires a definition of the center of the cell, and results might differ for different positions. | ||
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</math> | </math> | ||
Now, this makes only sense if <math>\rho_{\rm ions+valence}</math> drops to zero at some distance from <math>R_{\rm center}</math>. If this is | Now, this makes only sense if <math>\rho_{\rm ions+valence}</math> drops to zero at some distance from <math>\mathbf R_{\rm center}</math>. If this is | ||
not the case, the values are extremely sensible with respect to changes in <math>R_{\rm center}</math>. | not the case, the values are extremely sensible with respect to changes in <math>\mathbf R_{\rm center}</math>. | ||
Revision as of 17:39, 29 August 2012
(VASP.3.2 only)
DIPOL = [real array]
Default: DIPOL = Template:FIXME
For VASP.4.X behavior please refer to Monopole, Dipole and Quadrupole corrections.
It is possible to calculate the total dipole-moment in the cell, using the option
DIPOL=Rx Ry Rz
where Rx, Ry and Rz specify the center of the cell in direct lattice coordinates.
Mind: the calculation of the dipole requires a definition of the center of the cell, and results might differ for different positions. You should use this option only for surfaces and isolated molecules. In this case use the center of mass for the position (for surface only the component normal to the surface is meaningful).
The main problem is that the definition of the dipole 'destroys' the translational symmetry, i.e. the dipole is defined as
Now, this makes only sense if drops to zero at some distance from . If this is not the case, the values are extremely sensible with respect to changes in .
