MP2 ground state calculation - Tutorial - Revision history

Liebetreu: /* Actual MP2 calculations */

2026-04-13T14:21:12Z

Actual MP2 calculations

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	Depending on your choice, please switch to the corresponding page.		Depending on your choice, please switch to the corresponding page.

	<div style="background:~~#FFFFFF~~; border:solid 1px ~~#AAAAAA~~; padding:0.5em 1em; margin-right:14em;">		<div style="background:var(--vdefault-bg); border:solid 1px var(--vlines); padding:0.5em 1em; margin-right:14em;">
	# [[MP2\|MP2]]		# [[MP2\|MP2]]
	# [[LTMP2\|LTMP2]]		# [[LTMP2\|LTMP2]]

Huebsch at 10:20, 19 July 2022

2022-07-19T10:20:49Z

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	----		----
	[[Category:Many-~~Body Perturbation Theory~~]][[Category:MP2]][[Category:Tutorials]]		[[Category:Many-body perturbation theory]][[Category:MP2]][[Category:Tutorials]]

Karsai: Karsai moved page MP2 ground state calculation to MP2 ground state calculation - Tutorial

2019-06-07T13:30:58Z

Karsai moved page MP2 ground state calculation to MP2 ground state calculation - Tutorial

← Older revision	Revision as of 13:30, 7 June 2019
(No difference)

Karsai at 13:29, 7 June 2019

2019-06-07T13:29:34Z

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	{{Template:MP2}}		{{Template:MP2 - Tutorial}}

	This tutorial introduces how to calculate the ground state energy using second order Møller-Plesset perturbation theory (MP2) with VASP. Currently there are three implementations available:		This tutorial introduces how to calculate the ground state energy using second order Møller-Plesset perturbation theory (MP2) with VASP. Currently there are three implementations available:

Tobias at 18:14, 26 March 2019

2019-03-26T18:14:54Z

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	</references>		</references>

	[[Category:Tutorials]]		----
			[[Category:Many-Body Perturbation Theory]][[Category:MP2]][[Category:Tutorials]]

Karsai: /* Calculating the unoccupied Hartree-Fock orbitals */

2019-02-21T14:31:41Z

Calculating the unoccupied Hartree-Fock orbitals

← Older revision		Revision as of 14:31, 21 February 2019
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	Set the INCAR file to		Set the INCAR file to
	ISMEAR = 0 ; SIGMA = 0.01		{{TAGBL\|ISMEAR}} = 0 ; {{TAGBL\|SIGMA}} = 0.01
	ALGO = Exact		{{TAGBL\|ALGO}} = Exact
	LHFCALC = .TRUE. ; AEXX = 1.0		{{TAGBL\|LHFCALC}} = .TRUE. ; {{TAGBL\|AEXX}} = 1.0
	NELM = 1		{{TAGBL\|NELM}} = 1
	NBANDS = # number of plane-waves (favorably a multiple of the used mpi-ranks)		{{TAGBL\|NBANDS}} = # number of plane-waves (favorably a multiple of the used mpi-ranks)
	ENCUT = # same value as in the Hartree-Fock step		{{TAGBL\|ENCUT}} = # same value as in the Hartree-Fock step
	LORBITALREAL = .TRUE. # only necessary for LTMP2 and stochastic LTMP2		{{TAGBL\|LORBITALREAL}} = .TRUE. # only necessary for LTMP2 and stochastic LTMP2
	Make sure that VASP reads the {{TAG\|WAVECAR}} file from the previous Hartree-Fock step.		Make sure that VASP reads the {{TAG\|WAVECAR}} file from the previous Hartree-Fock step.

Karsai: /* Preparation: the Hartree-Fock ground state */

2019-02-21T14:30:37Z

Preparation: the Hartree-Fock ground state

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	== Preparation: the Hartree-Fock ground state ==		== Preparation: the Hartree-Fock ground state ==

	In order to calculate the Hartree-Fock ground state, use the following INCAR file		In order to calculate the Hartree-Fock ground state, use the following {{TAG\|INCAR}} file
	{{TAGBL\|ISMEAR}} = 0 ; SIGMA = 0.01		{{TAGBL\|ISMEAR}} = 0 ; {{TAGBL\|SIGMA}} = 0.01
	ALGO = A		{{TAGBL\|ALGO}} = A
	LHFCALC = .TRUE. ; AEXX = 1.0		{{TAGBL\|LHFCALC}} = .TRUE. ; {{TAGBL\|AEXX}} = 1.0
	EDIFF = 1E-6		{{TAGBL\|EDIFF}} = 1E-6
	ENCUT = # 10-20% larger than ENMAX in the POTCAR file		{{TAGBL\|ENCUT}} = # 10-20% larger than {{TAGBL\|ENMAX}} in the {{TAGBL\|POTCAR}} file
	LORBITALREAL = .TRUE. # only necessary for LTMP2 and stochastic LTMP2		{{TAGBL\|LORBITALREAL}} = .TRUE. # only necessary for LTMP2 and stochastic LTMP2
	Keep the {{TAG\|OUTCAR}} file to read-out the Hartree-Fock ground state energy later.		Keep the {{TAG\|OUTCAR}} file to read-out the Hartree-Fock ground state energy later.

Karsai: /* Preparation: the Hartree-Fock ground state */

2019-02-21T14:29:17Z

Preparation: the Hartree-Fock ground state

← Older revision		Revision as of 14:29, 21 February 2019
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	In order to calculate the Hartree-Fock ground state, use the following INCAR file		In order to calculate the Hartree-Fock ground state, use the following INCAR file
	ISMEAR = 0 ; SIGMA = 0.01		{{TAGBL\|ISMEAR}} = 0 ; SIGMA = 0.01
	ALGO = A		ALGO = A
	LHFCALC = .TRUE. ; AEXX = 1.0		LHFCALC = .TRUE. ; AEXX = 1.0

Tobias at 15:33, 31 January 2019

2019-01-31T15:33:53Z

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	We also need the unoccupied/virtual Hartree-Fock orbitals to perform MP2 calculations. The number of necessary orbitals should be equal to the number of plane-waves, that can be found via		We also need the unoccupied/virtual Hartree-Fock orbitals to perform MP2 calculations. The number of necessary orbitals should be equal to the number of plane-waves, that can be found via
	nplw=`awk '/number of plane-waves:/ {print $5} ' < ~~OUTCAR_OF_HARTREE_FOCK~~		nplw=`awk '/number of plane-waves:/ {print $5} ' < OUTCAR_HARTREE_FOCK_GROUND_STATE
	For the Gamma-only version of VASP, twice the number of plane-waves have to be used.		For the Gamma-only version of VASP, twice the number of plane-waves have to be used.

Tobias at 16:39, 28 January 2019

2019-01-28T16:39:57Z

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	* '''stochastic LTMP2'''<ref name="schaefer2018"/>: even faster calculations at the price of statistical noise can be achieved with the stochastic MP2 algorithm. It is an optimal choice for very large systems where only relative errors per valence electron are relevant. Keeping the absolute error fixed, the algorithm exhibits a cubic scaling with the system size, N³, whereas for a fixed relative error, a linear scaling, N¹, can be achieved. Note that there is no k-point sampling and no spin polarization implemented for this algorithm.		* '''stochastic LTMP2'''<ref name="schaefer2018"/>: even faster calculations at the price of statistical noise can be achieved with the stochastic MP2 algorithm. It is an optimal choice for very large systems where only relative errors per valence electron are relevant. Keeping the absolute error fixed, the algorithm exhibits a cubic scaling with the system size, N³, whereas for a fixed relative error, a linear scaling, N¹, can be achieved. Note that there is no k-point sampling and no spin polarization implemented for this algorithm.

	NOTE: If you use one of these algorithms, please cite the corresponding reference in your publication in addition to the standard VASP reference.		'''NOTE:''' ''If you use one of these algorithms, please cite the corresponding reference in your publication in addition to the standard VASP reference.''

	Both ''LTMP2'' as well as ''stochastic LTMP2'' are high performance algorithms that can parallelize the MP2 calculation over thousands of CPUs.		Both LTMP2 as well as stochastic LTMP2 are high performance algorithms that can parallelize the MP2 calculation over thousands of CPUs.

	<!--Furthermore, for very large systems, there is another technique to calcualte the MP2 ground state energy:		<!--Furthermore, for very large systems, there is another technique to calcualte the MP2 ground state energy: