LVACPOTAV - Revision history

Svijay at 09:24, 9 February 2024

2024-02-09T09:24:43Z

← Older revision		Revision as of 09:24, 9 February 2024
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	{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This choice is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}		{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This choice is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}
	{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}		{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}
	Before VASP 6.4.3, the default algorithm reports the 2D-averaged potential four grid points from the the minimum 2D-averaged charge density in the direction of {{TAG\|IDIPOL}}, i.e. no averaging is performed along the surface normal of the 2D-averaged potential.		Before VASP 6.4.3, the default algorithm reports the 2D-averaged potential four grid points from the the minimum 2D-averaged charge density in the direction of {{TAG\|IDIPOL}}, i.e., no averaging is performed along the surface normal of the 2D-averaged potential.
	=== Use in conjunction with the dipole correction ===		=== Use in conjunction with the dipole correction ===
	A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.		A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.

Svijay at 09:24, 9 February 2024

2024-02-09T09:24:18Z

← Older revision		Revision as of 09:24, 9 February 2024
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	{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This choice is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}		{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This choice is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}
	{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}		{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}
	Before VASP 6.4.3, the default algorithm reports the ~~slice~~-averaged potential ~~of a few~~ grid points ~~on both sides of~~ the minimum 2D-averaged charge density in the direction of {{TAG\|IDIPOL}}.		Before VASP 6.4.3, the default algorithm reports the 2D-averaged potential four grid points from the the minimum 2D-averaged charge density in the direction of {{TAG\|IDIPOL}}, i.e. no averaging is performed along the surface normal of the 2D-averaged potential.
	=== Use in conjunction with the dipole correction ===		=== Use in conjunction with the dipole correction ===
	A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.		A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.

Svijay at 16:40, 6 February 2024

2024-02-06T16:40:52Z

← Older revision		Revision as of 16:40, 6 February 2024
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	Note that two vacuum potentials will be produced, one corresponding to the upper termination of the slab and one corresponding to the lower. Depending on the system, one might be more interesting than the other.		Note that two vacuum potentials will be produced, one corresponding to the upper termination of the slab and one corresponding to the lower. Depending on the system, one might be more interesting than the other.
	{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}		{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This choice is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}
	{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}		{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}
	Before VASP 6.4.3, the default algorithm reports the slice-averaged potential of a few grid points on both sides of the minimum 2D-averaged charge density in ~~all directions (regardless~~ of {{TAG\|IDIPOL}}).		Before VASP 6.4.3, the default algorithm reports the slice-averaged potential of a few grid points on both sides of the minimum 2D-averaged charge density in the direction of {{TAG\|IDIPOL}}.
	=== Use in conjunction with the dipole correction ===		=== Use in conjunction with the dipole correction ===
	A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.		A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.

Huebsch: /* Related tags and articles */

2024-02-06T10:51:01Z

Huebsch at 10:43, 6 February 2024

2024-02-06T10:43:40Z

← Older revision		Revision as of 10:43, 6 February 2024
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	~~'''~~LVACPOTAV~~''' =~~ .~~TRUE~~. \| .~~FALSE~~.		{{TAGDEF\|LVACPOTAV\|.True. {{!}} .False.\|.False.}}

	~~Default~~: ~~'''LVACPOTAV''' = .FALSE~~.		Description: Switch on determining the vacuum potential by averaging the local potential over a field-free region.
	----		----

	~~Description: Determine~~ the vacuum potential by averaging the ~~local~~ potential ~~over~~ a ~~field~~-~~free region~~		{{TAG\|LVACPOTAV}} switches on the computation of the vacuum potential, i.e., the average of the local potential in the vacuum region.
			It computes the average potential by searching regions that are field-free ({{TAG\|VACPOTFLAT}}), and the 2D-averaged charge density is nearly zero. The averaging is done in the direction of {{TAG\|IDIPOL}} and is reported as the vacuum potential in the {{FILE\|OUTCAR}}.
			{{NB\|tip\| As {{TAG\|LVACPOTAV}} performs a post-processing step, you may use it together with {{TAG\|ALGO}} {{=}} None by restarting a converged calculation.}}
			The vacuum potential is one of the quantities needed to [[Computing the work function\|compute the work function]]. It can be extracted from the {{FILE\|OUTCAR}} by the following bash command

	~~This tag switches on the computation of the vacuum potential; i.e. the average of the local potential in the vacuum region.~~		grep upper OUTCAR
	It computes the average potential by iterating over regions of the 2D-averaged charge density (averaging done in the direction of [[IDIPOL]]) and tries to find a region in the cell where the charge density is nearly zero (corresponding to a field-free region in a cell without any compensating background charge).
	~~The potential is averaged over this region and is reported as the vacuum potential.~~
	~~{{NB\|warning\| Note that '''LVACPOTAV''' is currently implemented for {{TAG\|IDIPOL}} between 1 and 3.}}~~
	{{NB\|tip\| As this tag performs a post-processing step to the calculation, you may use it together with {{TAG\|ALGO}} {{=}} None for a quick look at the vacuum potentials after a converged calculation.}}

	The vacuum potential is one of the quantities needed to compute the workfunction (see [[Computing the work function\|here]] for a step-by-step guide on how to compute the workfunction with VASP). The vacuum potentials are written to the [[OUTCAR]] file and can be accessed with the following bash command

	~~<code>~~grep upper OUTCAR~~</code>~~

	which will produce the vacuum potentials. Note that two vacuum potentials will be produced, one corresponding to the upper termination of the slab and one corresponding to the lower. Depending on the system you are studying, one might be more interesting than another.
	{{NB\|tip\| In case you would like to determine the workfunction, we suggest using '''LVACPOTAV''' along with the [[LVHAR]] tag such that only the sum of the Hartree and Ionic potentials are used in the calculation of the vacuum potential.}}

			Note that two vacuum potentials will be produced, one corresponding to the upper termination of the slab and one corresponding to the lower. Depending on the system, one might be more interesting than the other.
			{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}
			{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}
			Before VASP 6.4.3, the default algorithm reports the slice-averaged potential of a few grid points on both sides of the minimum 2D-averaged charge density in all directions (regardless of {{TAG\|IDIPOL}}).
	=== Use in conjunction with the dipole correction ===		=== Use in conjunction with the dipole correction ===
	A typical use case for ~~this tag~~ is together with the dipole correction (including tags [[LDIPOL]] and [[IDIPOL]]). Switching on the dipole correction is crucial for determining the vacuum potential; without ~~using~~ it there will be no field free region for dipolar systems.		A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.
			{{NB\|mind\| Note that {{TAG\|LVACPOTAV}} is currently implemented for {{TAG\|IDIPOL}} between 1 and 3.}}

	=== Warnings ===		=== Warnings ===
	In case ~~'''~~LVACPOTAV~~'''~~ is not able to generate an accurate ~~workfunction~~, the following warnings may be found in the [[OUTCAR]] file.		In case {{TAG\|LVACPOTAV}} is not able to generate an accurate work function, the following warnings may be found in the {{FILE\|OUTCAR}} file.

	==== Vacuum region is likely too small ====		==== Vacuum region is likely too small ====
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	Possible solutions include:		Possible solutions include:

	* Making sure you have a large enough vacuum dimension		* Making sure you have a large enough vacuum dimension.
	* Increasing the precision of your calculation by changing ~~[[EDIFF]]~~		* Increasing the precision of your calculation by changing {{TAG\|EDIFF}}.
	{{NB\|warning\| This tag is available only for versions after 6.4.3. Prior to this version, the default algorithm used to determine the vacuum potential is used. The default algorithm simply reports the slice-averaged potential in all directions apart from {{TAG\|~~IDIPOL~~}} ~~a few grid points on either direction of the minimum 2D-averaged charge density~~.}}

	== Related tags and articles ==		== Related tags and articles ==
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	{{TAG\|LDIPOL}},		{{TAG\|LDIPOL}},
	{{TAG\|IDIPOL}},		{{TAG\|IDIPOL}},
	{{TAG\|VACPOTFLAT}}		{{TAG\|VACPOTFLAT}},
			{{TAG\|WRT_POTENTIAL}},
			{{TAG\|LVTOT}},
			{{TAG\|LVHAR}}

	[[Category:Electrostatics]][[Category:INCAR tag]]		[[Category:Electrostatics]][[Category:INCAR tag]]

Svijay at 10:40, 5 February 2024

2024-02-05T10:40:28Z

← Older revision		Revision as of 10:40, 5 February 2024
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	Default: '''LVACPOTAV''' = .FALSE.		Default: '''LVACPOTAV''' = .FALSE.
			----

	Description: Determine the vacuum potential by averaging the local potential over a field-free region		Description: Determine the vacuum potential by averaging the local potential over a field-free region

Svijay: Change to LVACPOTAV

2024-02-05T09:58:27Z

Change to LVACPOTAV

← Older revision		Revision as of 09:58, 5 February 2024
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	'''~~VACPOTAV~~''' = .TRUE. \| .FALSE.		'''LVACPOTAV''' = .TRUE. \| .FALSE.

	Default: '''~~VACPOTAV~~''' = .FALSE.		Default: '''LVACPOTAV''' = .FALSE.

	Description: Determine the vacuum potential by averaging the local potential over a field-free region		Description: Determine the vacuum potential by averaging the local potential over a field-free region
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	It computes the average potential by iterating over regions of the 2D-averaged charge density (averaging done in the direction of [[IDIPOL]]) and tries to find a region in the cell where the charge density is nearly zero (corresponding to a field-free region in a cell without any compensating background charge).		It computes the average potential by iterating over regions of the 2D-averaged charge density (averaging done in the direction of [[IDIPOL]]) and tries to find a region in the cell where the charge density is nearly zero (corresponding to a field-free region in a cell without any compensating background charge).
	The potential is averaged over this region and is reported as the vacuum potential.		The potential is averaged over this region and is reported as the vacuum potential.
	{{NB\|warning\| Note that '''~~VACPOTAV~~''' is currently implemented for {{TAG\|IDIPOL}} between 1 and 3.}}		{{NB\|warning\| Note that '''LVACPOTAV''' is currently implemented for {{TAG\|IDIPOL}} between 1 and 3.}}
	{{NB\|tip\| As this tag performs a post-processing step to the calculation, you may use it together with {{TAG\|ALGO}} {{=}} None for a quick look at the vacuum potentials after a converged calculation.}}		{{NB\|tip\| As this tag performs a post-processing step to the calculation, you may use it together with {{TAG\|ALGO}} {{=}} None for a quick look at the vacuum potentials after a converged calculation.}}

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	which will produce the vacuum potentials. Note that two vacuum potentials will be produced, one corresponding to the upper termination of the slab and one corresponding to the lower. Depending on the system you are studying, one might be more interesting than another.		which will produce the vacuum potentials. Note that two vacuum potentials will be produced, one corresponding to the upper termination of the slab and one corresponding to the lower. Depending on the system you are studying, one might be more interesting than another.
	{{NB\|tip\| In case you would like to determine the workfunction, we suggest using '''~~VACPOTAV~~''' along with the [[LVHAR]] tag such that only the sum of the Hartree and Ionic potentials are used in the calculation of the vacuum potential.}}		{{NB\|tip\| In case you would like to determine the workfunction, we suggest using '''LVACPOTAV''' along with the [[LVHAR]] tag such that only the sum of the Hartree and Ionic potentials are used in the calculation of the vacuum potential.}}

	=== Use in conjunction with the dipole correction ===		=== Use in conjunction with the dipole correction ===
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	=== Warnings ===		=== Warnings ===
	In case '''~~VACPOTAV~~''' is not able to generate an accurate workfunction, the following warnings may be found in the [[OUTCAR]] file.		In case '''LVACPOTAV''' is not able to generate an accurate workfunction, the following warnings may be found in the [[OUTCAR]] file.

	==== Vacuum region is likely too small ====		==== Vacuum region is likely too small ====

Svijay: Svijay moved page VACPOTAV to LVACPOTAV: Change in tag name

2024-02-05T09:57:14Z

Svijay moved page VACPOTAV to LVACPOTAV: Change in tag name

← Older revision

Revision as of 09:57, 5 February 2024

Svijay at 09:49, 5 February 2024

2024-02-05T09:49:38Z

← Older revision		Revision as of 09:49, 5 February 2024
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	The potential is averaged over this region and is reported as the vacuum potential.		The potential is averaged over this region and is reported as the vacuum potential.
	{{NB\|warning\| Note that '''VACPOTAV''' is currently implemented for {{TAG\|IDIPOL}} between 1 and 3.}}		{{NB\|warning\| Note that '''VACPOTAV''' is currently implemented for {{TAG\|IDIPOL}} between 1 and 3.}}
			{{NB\|tip\| As this tag performs a post-processing step to the calculation, you may use it together with {{TAG\|ALGO}} {{=}} None for a quick look at the vacuum potentials after a converged calculation.}}

	The vacuum potential is one of the quantities needed to compute the workfunction (see [[Computing the work function\|here]] for a step-by-step guide on how to compute the workfunction with VASP). The vacuum potentials are written to the [[OUTCAR]] file and can be accessed with the following bash command		The vacuum potential is one of the quantities needed to compute the workfunction (see [[Computing the work function\|here]] for a step-by-step guide on how to compute the workfunction with VASP). The vacuum potentials are written to the [[OUTCAR]] file and can be accessed with the following bash command

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	* Increasing the precision of your calculation by changing [[EDIFF]]		* Increasing the precision of your calculation by changing [[EDIFF]]
	{{NB\|warning\| This tag is available only for versions after 6.4.3. Prior to this version, the default algorithm used to determine the vacuum potential is used. The default algorithm simply reports the slice-averaged potential in all directions apart from {{TAG\|IDIPOL}} a few grid points on either direction of the minimum 2D-averaged charge density.}}		{{NB\|warning\| This tag is available only for versions after 6.4.3. Prior to this version, the default algorithm used to determine the vacuum potential is used. The default algorithm simply reports the slice-averaged potential in all directions apart from {{TAG\|IDIPOL}} a few grid points on either direction of the minimum 2D-averaged charge density.}}


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

Svijay at 09:39, 5 February 2024

2024-02-05T09:39:00Z

← Older revision		Revision as of 09:39, 5 February 2024
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	* Making sure you have a large enough vacuum dimension		* Making sure you have a large enough vacuum dimension
	* Increasing the precision of your calculation by changing [[EDIFF]]		* Increasing the precision of your calculation by changing [[EDIFF]]

	{{NB\|warning\| This tag is available only for versions after 6.4.3. Prior to this version, the default algorithm used to determine the vacuum potential is used. The default algorithm simply reports the slice-averaged potential in all directions apart from {{TAG\|IDIPOL}} a few grid points on either direction of the minimum 2D-averaged charge density.}}		{{NB\|warning\| This tag is available only for versions after 6.4.3. Prior to this version, the default algorithm used to determine the vacuum potential is used. The default algorithm simply reports the slice-averaged potential in all directions apart from {{TAG\|IDIPOL}} a few grid points on either direction of the minimum 2D-averaged charge density.}}

← Older revision		Revision as of 09:24, 9 February 2024
Line 14:		Line 14:
	{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This choice is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}		{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This choice is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}
	{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}		{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}
	Before VASP 6.4.3, the default algorithm reports the 2D-averaged potential four grid points from the the minimum 2D-averaged charge density in the direction of {{TAG\|IDIPOL}}, i.e. no averaging is performed along the surface normal of the 2D-averaged potential.		Before VASP 6.4.3, the default algorithm reports the 2D-averaged potential four grid points from the the minimum 2D-averaged charge density in the direction of {{TAG\|IDIPOL}}, i.e., no averaging is performed along the surface normal of the 2D-averaged potential.
	=== Use in conjunction with the dipole correction ===		=== Use in conjunction with the dipole correction ===
	A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.		A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.

← Older revision		Revision as of 09:24, 9 February 2024
Line 14:		Line 14:
	{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This choice is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}		{{NB\|tip\|For determining the work function, we suggest using {{TAG\|LVACPOTAV}} along with the {{TAG\|LVHAR}} tag such that only the sum of the Hartree and ionic potentials are used in the calculation of the vacuum potential. This choice is because the exchange-correlation potential might be noisy in the vacuum region but should, in principle, be zero.}}
	{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}		{{NB\|mind\|{{TAG\|LVACPOTAV}} is available only for versions after 6.4.3.}}
	Before VASP 6.4.3, the default algorithm reports the ~~slice~~-averaged potential ~~of a few~~ grid points ~~on both sides of~~ the minimum 2D-averaged charge density in the direction of {{TAG\|IDIPOL}}.		Before VASP 6.4.3, the default algorithm reports the 2D-averaged potential four grid points from the the minimum 2D-averaged charge density in the direction of {{TAG\|IDIPOL}}, i.e. no averaging is performed along the surface normal of the 2D-averaged potential.
	=== Use in conjunction with the dipole correction ===		=== Use in conjunction with the dipole correction ===
	A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.		A typical use case for {{TAG\|LVACPOTAV}} is together with the dipole correction (including tags {{TAG\|LDIPOL}} and {{TAG\|IDIPOL}}). Switching on the dipole correction is crucial for determining the vacuum potential; without it, there will be no field-free region for dipolar systems.

← Older revision		Revision as of 10:51, 6 February 2024
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	{{TAG\|LVTOT}},		{{TAG\|LVTOT}},
	{{TAG\|LVHAR}}		{{TAG\|LVHAR}}

			[[Computing the work function]]

	[[Category:Electrostatics]][[Category:INCAR tag]]		[[Category:Electrostatics]][[Category:INCAR tag]]