LDIPOL - Revision history

Hampel at 10:28, 17 February 2025

2025-02-17T10:28:59Z

← Older revision		Revision as of 10:28, 17 February 2025
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	Furthermore, finite-size errors affect the potential and the forces.		Furthermore, finite-size errors affect the potential and the forces.
	This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.		This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.
	For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells, a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.		For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells, a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions. When activating this tag the tag {{TAG\|IDIPOL}} has to be specified, and optionally the tag {{TAG\|DIPOL}} as well.
	{{NB\|mind\| This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy. }}		{{NB\|mind\| This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy. }}

Huebsch at 13:33, 1 November 2023

2023-11-01T13:33:11Z

Svijay at 09:12, 20 October 2023

2023-10-20T09:12:15Z

← Older revision		Revision as of 09:12, 20 October 2023
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	[[Category:INCAR tag]][[Category:Ionic minimization]][[Category:Forces]][[Category:~~Monopole Dipole and Quadrupole Corrections~~]]		[[Category:INCAR tag]][[Category:Ionic minimization]][[Category:Forces]][[Category:Electrostatics]]

Schlipf at 09:51, 19 October 2023

2023-10-19T09:51:19Z

← Older revision		Revision as of 09:51, 19 October 2023
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	----		----

	~~Due to the~~ periodic boundary conditions~~, not only~~ the total energy ~~converges slowly~~ with ~~respect to~~ the size of the supercell, ~~but~~ the potential and the forces ~~are also affected by finite-size errors~~. This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.		The presence of a dipole in combination with periodic boundary conditions leads to a slow convergence of the total energy with the size of the supercell.
			Furthermore, finite-size errors affect the potential and the forces.
			This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.
	For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.		For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.
	{{NB\|mind\| This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy. }}		{{NB\|mind\| This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy. }}

Svijay: Move tips to the corrections page

2023-10-19T09:34:30Z

Move tips to the corrections page

← Older revision		Revision as of 09:34, 19 October 2023
Line 10:		Line 10:
	The biggest advantage of this mode is that leading errors in the forces are corrected and that the workfunction can be evaluated for asymmetric slabs. The disadvantage is that the convergence to the electronic ground state might slow down considerably, i.e., more electronic iterations might be required to obtain the required precision.		The biggest advantage of this mode is that leading errors in the forces are corrected and that the workfunction can be evaluated for asymmetric slabs. The disadvantage is that the convergence to the electronic ground state might slow down considerably, i.e., more electronic iterations might be required to obtain the required precision.
	{{NB\|warning\| For charged systems, the potential correction is currently only implemented for cubic supercells. VASP will stop if the supercell is not cubic and {{TAG\|LDIPOL}} is used. }}		{{NB\|warning\| For charged systems, the potential correction is currently only implemented for cubic supercells. VASP will stop if the supercell is not cubic and {{TAG\|LDIPOL}} is used. }}
			<!---

	== Tips for improving convergence ==		== Tips for improving convergence ==
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	3. Ensure that the cell is sufficiently large to determine the dipole moment with sufficient accuracy (see {{TAG\|DIPOL}}). If the cell is too small, the charge might slash through the vacuum, causing very slow convergence. Often convergence improves with the size of the supercell.		3. Ensure that the cell is sufficiently large to determine the dipole moment with sufficient accuracy (see {{TAG\|DIPOL}}). If the cell is too small, the charge might slash through the vacuum, causing very slow convergence. Often convergence improves with the size of the supercell.

			-->

	== Related tags and articles ==		== Related tags and articles ==

Svijay: refactor text - tips for convergence

2023-10-18T12:21:32Z

refactor text - tips for convergence

← Older revision		Revision as of 12:21, 18 October 2023
Line 4:		Line 4:
	----		----

	Due to the periodic boundary conditions, not only the total energy converges slowly with respect to the size of the supercell, but ~~also~~ the potential and the forces are affected by finite-size errors. This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.		Due to the periodic boundary conditions, not only the total energy converges slowly with respect to the size of the supercell, but the potential and the forces are also affected by finite-size errors. This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.
	For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.		For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.
	This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy.		{{NB\|mind\| This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy. }}

	The biggest advantage of this mode is that leading errors in the forces are corrected and that the ~~work function~~ can be evaluated for asymmetric slabs. The disadvantage is that the convergence to the electronic ground state might slow down considerably, i.e., more electronic iterations might be required to obtain the required precision. ~~It is recommended to use this mode only after pre-converging the orbitals without the~~ {{~~TAG~~\|~~LDIPOL}} tag~~, ~~and~~ the ~~center of charge should be set in~~ the ~~{{FILE\|INCAR}} file (~~{{TAG\|~~DIPOL~~}}~~= center of mass. The user must also ensure that the cell~~ is sufficiently large to determine the dipole moment with sufficient accuracy. If the cell is too small, the charge might slash through the vacuum, causing very slow convergence. Often convergence improves with the size of the supercell.		The biggest advantage of this mode is that leading errors in the forces are corrected and that the workfunction can be evaluated for asymmetric slabs. The disadvantage is that the convergence to the electronic ground state might slow down considerably, i.e., more electronic iterations might be required to obtain the required precision.
			{{NB\|warning\| For charged systems, the potential correction is currently only implemented for cubic supercells. VASP will stop if the supercell is not cubic and {{TAG\|LDIPOL}} is used. }}

	~~Restrictions: For charged systems, the potential correction is currently only implemented~~ for ~~cubic supercells~~. ~~VASP will stop if~~ the ~~supercell is not cubic and~~ {{TAG\|LDIPOL}}=.~~TRUE~~.		== Tips for improving convergence ==

			1. Use this mode only after pre-converging the orbitals without the {{TAG\|LDIPOL}} tag

			2. The center of charge should be set in the {{FILE\|INCAR}} file ({{TAG\|DIPOL}}= center of mass)

			3. Ensure that the cell is sufficiently large to determine the dipole moment with sufficient accuracy (see {{TAG\|DIPOL}}). If the cell is too small, the charge might slash through the vacuum, causing very slow convergence. Often convergence improves with the size of the supercell.

	== Related tags and articles ==		== Related tags and articles ==

Huebsch at 08:26, 7 April 2022

2022-04-07T08:26:36Z

← Older revision		Revision as of 08:26, 7 April 2022
Line 12:		Line 12:
	Restrictions: For charged systems, the potential correction is currently only implemented for cubic supercells. VASP will stop if the supercell is not cubic and {{TAG\|LDIPOL}}=.TRUE.		Restrictions: For charged systems, the potential correction is currently only implemented for cubic supercells. VASP will stop if the supercell is not cubic and {{TAG\|LDIPOL}}=.TRUE.

	== Related ~~Tags~~ and ~~Sections~~ ==		== Related tags and articles ==
	{{TAG\|Monopole Dipole and Quadrupole corrections}},		{{TAG\|Monopole Dipole and Quadrupole corrections}},
	{{TAG\|NELECT}},		{{TAG\|NELECT}},
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	[[Category:INCAR]][[Category:~~Structural Optimization~~]][[Category:Forces~~]][[Category:Atoms and Molecules~~]][[Category:Monopole Dipole and Quadrupole Corrections]]		[[Category:INCAR tag]][[Category:Ionic minimization]][[Category:Forces]][[Category:Monopole Dipole and Quadrupole Corrections]]

Huebsch at 02:07, 18 August 2021

2021-08-18T02:07:50Z

← Older revision		Revision as of 02:07, 18 August 2021
Line 1:		Line 1:
	{{TAGDEF\|LDIPOL\|.TRUE. {{!}} .FALSE.\|.FALSE.}}		{{TAGDEF\|LDIPOL\|.TRUE. {{!}} .FALSE.\|.FALSE.}}

	Description: {{TAG\|LDIPOL}} switches on corrections to the potential and forces in VASP. Can be applied for charged molecules and molecules and slabs with a net dipole moment.		Description: {{TAG\|LDIPOL}} switches on corrections to the potential and forces in VASP. Can be applied for charged molecules and molecules and slabs with a net dipole moment.
	----		----
	Due to the periodic boundary conditions, not only the total energy converges slowly with respect to the size of the supercell, but also the potential and the forces are affected by finite size errors. This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.
	For LDIPOL=.TRUE.,a linear correction and for charged cells a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.
	This is in the spirit of Neugebauer ''et al.''<ref name="Neugebauer92"/> (but more general and the total energy is correctly implemented, whereas the Neugebauer paper contains an erroneous factor 2 in the total energy). The biggest advantage of this mode is that leading errors in the forces are corrected, and that the work-function can be evaluated for asymmetric slabs. The disadvantage is that the convergence to the electronic groundstate might slow down considerably (''i.e.'', more electronic iterations might be required to obtain the required precision). It is recommended to use this mode only after pre-converging the orbitals without the {{TAG\|LDIPOL}} flag, and the center of charge should be set in the {{FILE\|INCAR}} file ({{TAG\|DIPOL}}= center of mass). The user must also ensure that the cell is sufficiently large to determine the dipole moment with sufficient accuracy. If the cell is too small, charge might slash through the vacuum, causing very slow convergence (often convergence improves with the size of the supercell).

	Restrictions: ~~for~~ charged systems, the potential correction is currently only implemented		Due to the periodic boundary conditions, not only the total energy converges slowly with respect to the size of the supercell, but also the potential and the forces are affected by finite-size errors. This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.
	for cubic supercells. VASP will stop if the supercell is not cubic and {{TAG\|LDIPOL}}=.TRUE.		For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.
			This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy.

			The biggest advantage of this mode is that leading errors in the forces are corrected and that the work function can be evaluated for asymmetric slabs. The disadvantage is that the convergence to the electronic ground state might slow down considerably, i.e., more electronic iterations might be required to obtain the required precision. It is recommended to use this mode only after pre-converging the orbitals without the {{TAG\|LDIPOL}} tag, and the center of charge should be set in the {{FILE\|INCAR}} file ({{TAG\|DIPOL}}= center of mass. The user must also ensure that the cell is sufficiently large to determine the dipole moment with sufficient accuracy. If the cell is too small, the charge might slash through the vacuum, causing very slow convergence. Often convergence improves with the size of the supercell.

			Restrictions: For charged systems, the potential correction is currently only implemented for cubic supercells. VASP will stop if the supercell is not cubic and {{TAG\|LDIPOL}}=.TRUE.

	== Related Tags and Sections ==		== Related Tags and Sections ==
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	== References ==		== References ==
	~~<references>~~
	~~<ref name="Neugebauer92">[http://dx.doi.org/10.1103/PhysRevB.46.16067 J. Neugebauer and M. Scheffler, Phys. Rev. B 46, 16067 (1992).]</ref>~~
	~~</references>~~
	~~----~~

	[[Category:INCAR]][[Category:Structural Optimization]][[Category:Forces]][[Category:Atoms and Molecules]][[Category:Monopole Dipole and Quadrupole Corrections]]		[[Category:INCAR]][[Category:Structural Optimization]][[Category:Forces]][[Category:Atoms and Molecules]][[Category:Monopole Dipole and Quadrupole Corrections]]

Karsai at 14:27, 24 June 2019

2019-06-24T14:27:21Z

← Older revision		Revision as of 14:27, 24 June 2019
Line 27:		Line 27:
	----		----

	[[Category:INCAR]][[Category:Structural Optimization]][[Category:Forces]][[Category:Molecules]][[Category:Monopole Dipole and Quadrupole Corrections]]		[[Category:INCAR]][[Category:Structural Optimization]][[Category:Forces]][[Category:Atoms and Molecules]][[Category:Monopole Dipole and Quadrupole Corrections]]

Karsai at 16:28, 16 April 2019

2019-04-16T16:28:36Z

← Older revision		Revision as of 16:28, 16 April 2019
Line 27:		Line 27:
	----		----

	[[Category:INCAR]][[Category:Structural Optimization]][[Category:Forces]]		[[Category:INCAR]][[Category:Structural Optimization]][[Category:Forces]][[Category:Molecules]][[Category:Monopole Dipole and Quadrupole Corrections]]

← Older revision		Revision as of 12:21, 18 October 2023
Line 4:		Line 4:
	----		----

	Due to the periodic boundary conditions, not only the total energy converges slowly with respect to the size of the supercell, but ~~also~~ the potential and the forces are affected by finite-size errors. This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.		Due to the periodic boundary conditions, not only the total energy converges slowly with respect to the size of the supercell, but the potential and the forces are also affected by finite-size errors. This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.
	For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.		For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.
	This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy.		{{NB\|mind\| This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy. }}

	The biggest advantage of this mode is that leading errors in the forces are corrected and that the ~~work function~~ can be evaluated for asymmetric slabs. The disadvantage is that the convergence to the electronic ground state might slow down considerably, i.e., more electronic iterations might be required to obtain the required precision. ~~It is recommended to use this mode only after pre-converging the orbitals without the~~ {{~~TAG~~\|~~LDIPOL}} tag~~, ~~and~~ the ~~center of charge should be set in~~ the ~~{{FILE\|INCAR}} file (~~{{TAG\|~~DIPOL~~}}~~= center of mass. The user must also ensure that the cell~~ is sufficiently large to determine the dipole moment with sufficient accuracy. If the cell is too small, the charge might slash through the vacuum, causing very slow convergence. Often convergence improves with the size of the supercell.		The biggest advantage of this mode is that leading errors in the forces are corrected and that the workfunction can be evaluated for asymmetric slabs. The disadvantage is that the convergence to the electronic ground state might slow down considerably, i.e., more electronic iterations might be required to obtain the required precision.
			{{NB\|warning\| For charged systems, the potential correction is currently only implemented for cubic supercells. VASP will stop if the supercell is not cubic and {{TAG\|LDIPOL}} is used. }}

	~~Restrictions: For charged systems, the potential correction is currently only implemented~~ for ~~cubic supercells~~. ~~VASP will stop if~~ the ~~supercell is not cubic and~~ {{TAG\|LDIPOL}}=.~~TRUE~~.		== Tips for improving convergence ==

			1. Use this mode only after pre-converging the orbitals without the {{TAG\|LDIPOL}} tag

			2. The center of charge should be set in the {{FILE\|INCAR}} file ({{TAG\|DIPOL}}= center of mass)

			3. Ensure that the cell is sufficiently large to determine the dipole moment with sufficient accuracy (see {{TAG\|DIPOL}}). If the cell is too small, the charge might slash through the vacuum, causing very slow convergence. Often convergence improves with the size of the supercell.

	== Related tags and articles ==		== Related tags and articles ==

← Older revision		Revision as of 13:33, 1 November 2023
Line 1:		Line 1:
	{{TAGDEF\|LDIPOL\|.TRUE. {{!}} .FALSE.\|.FALSE.}}		{{TAGDEF\|LDIPOL\|.TRUE. {{!}} .FALSE.\|.FALSE.}}

	Description: {{TAG\|LDIPOL}} switches on corrections to the potential and forces ~~in VASP~~. Can be applied for charged ~~molecules and~~ molecules and slabs with a net dipole moment.		Description: {{TAG\|LDIPOL}} switches on corrections to the potential and forces. Can be applied for charged molecules and slabs with a net dipole moment.
	----		----

Line 7:		Line 7:
	Furthermore, finite-size errors affect the potential and the forces.		Furthermore, finite-size errors affect the potential and the forces.
	This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.		This effect can be counterbalanced by setting {{TAG\|LDIPOL}}=.TRUE. in the {{FILE\|INCAR}} file.
	For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.		For {{TAG\|LDIPOL}}=.TRUE., a linear correction, and for charged cells, a quadratic electrostatic potential is added to the local potential in order to correct the errors introduced by the periodic boundary conditions.
	{{NB\|mind\| This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy. }}		{{NB\|mind\| This is in the spirit of Neugebauer ''et al.'' {{cite\|neugebauer:prb:1992}}, though more general. Note that the total energy is correctly implemented, whereas Ref. {{cite\|neugebauer:prb:1992}} contains an erroneous factor 2 in the total energy. }}

	The biggest advantage of this mode is that leading errors in the forces are corrected and that the ~~workfunction~~ can be evaluated for asymmetric slabs. The disadvantage is that the convergence to the electronic ground state might slow down considerably, i.e., more electronic iterations might be required to obtain the required precision.		The biggest advantage of this mode is that leading errors in the forces are corrected and that the work function can be evaluated for asymmetric slabs. The disadvantage is that the convergence to the electronic ground state might slow down considerably, i.e., more electronic iterations might be required to obtain the required precision.
	{{NB\|warning\| For charged systems, the potential correction is currently only implemented for cubic supercells. VASP will stop if the supercell is not cubic and {{TAG\|LDIPOL}} is used. }}		{{NB\|warning\| For charged systems, the potential correction is currently only implemented for cubic supercells. VASP will stop if the supercell is not cubic and {{TAG\|LDIPOL}} is used. }}
	<!---		<!---
Line 20:		Line 20:
	2. The center of charge should be set in the {{FILE\|INCAR}} file ({{TAG\|DIPOL}}= center of mass)		2. The center of charge should be set in the {{FILE\|INCAR}} file ({{TAG\|DIPOL}}= center of mass)

	3. Ensure that the cell is sufficiently large to determine the dipole moment with sufficient accuracy (see {{TAG\|DIPOL}}). If the cell is too small, the charge might slash through the vacuum, causing very slow convergence. Often convergence improves with the size of the supercell.		3. Ensure that the cell is sufficiently large to determine the dipole moment with sufficient accuracy (see {{TAG\|DIPOL}}). If the cell is too small, the charge might slash through the vacuum, causing very slow convergence. Often, convergence improves with the size of the supercell.

	-->		-->