Calculating the chemical shieldings - Revision history

Csheldon: /* Additional tags */

2025-03-31T08:06:51Z

Additional tags

← Older revision		Revision as of 08:06, 31 March 2025
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	Several additional {{FILE\|INCAR}} tags should be considered. Specifically, {{TAG\|LASPH}} should be set to <code>.TRUE.</code>, turning on the non-spherical contributions to the gradient of the density inside the PAW spheres. Occasionally, e.g. for systems containing H or first-row elements, and short bonds, the two-center contributions to the augmentation currents in the PAW spheres are important. In this case, {{TAG\|LLRAUG}} = .TRUE. should be used {{Cite\|dewijs:jcp:2013}}{{Cite\|dewijs:jcp:2021}}.		Several additional {{FILE\|INCAR}} tags should be considered. Specifically, {{TAG\|LASPH}} should be set to <code>.TRUE.</code>, turning on the non-spherical contributions to the gradient of the density inside the PAW spheres. Occasionally, e.g. for systems containing H or first-row elements, and short bonds, the two-center contributions to the augmentation currents in the PAW spheres are important. In this case, {{TAG\|LLRAUG}} = .TRUE. should be used {{Cite\|dewijs:jcp:2013}}{{Cite\|dewijs:jcp:2021}}.

	Calculating the chemical shift can also be sped up by utilizing parallelisation. If you are using multiple k-points, then you can treat these in parallel using {{TAG\|KPAR}}.		Calculating the chemical shift can also be sped up by utilizing parallelisation. If you are using multiple k-points, then you can treat these in parallel using {{TAG\|KPAR}}, reducing the overall calculation time.
	{{NB\|important\|The treatment of the orbital magnetism is non-relativistic. This is suitable for light nuclei.		{{NB\|important\|The treatment of the orbital magnetism is non-relativistic. This is suitable for light nuclei.
	The standard POTCARs are scalar-relativistic and account partially for relativistic effects.		The standard POTCARs are scalar-relativistic and account partially for relativistic effects.

Csheldon: /* Additional tags */

2025-03-31T08:04:38Z

Additional tags

← Older revision		Revision as of 08:04, 31 March 2025
Line 41:		Line 41:

	Several additional {{FILE\|INCAR}} tags should be considered. Specifically, {{TAG\|LASPH}} should be set to <code>.TRUE.</code>, turning on the non-spherical contributions to the gradient of the density inside the PAW spheres. Occasionally, e.g. for systems containing H or first-row elements, and short bonds, the two-center contributions to the augmentation currents in the PAW spheres are important. In this case, {{TAG\|LLRAUG}} = .TRUE. should be used {{Cite\|dewijs:jcp:2013}}{{Cite\|dewijs:jcp:2021}}.		Several additional {{FILE\|INCAR}} tags should be considered. Specifically, {{TAG\|LASPH}} should be set to <code>.TRUE.</code>, turning on the non-spherical contributions to the gradient of the density inside the PAW spheres. Occasionally, e.g. for systems containing H or first-row elements, and short bonds, the two-center contributions to the augmentation currents in the PAW spheres are important. In this case, {{TAG\|LLRAUG}} = .TRUE. should be used {{Cite\|dewijs:jcp:2013}}{{Cite\|dewijs:jcp:2021}}.

			Calculating the chemical shift can also be sped up by utilizing parallelisation. If you are using multiple k-points, then you can treat these in parallel using {{TAG\|KPAR}}.
	{{NB\|important\|The treatment of the orbital magnetism is non-relativistic. This is suitable for light nuclei.		{{NB\|important\|The treatment of the orbital magnetism is non-relativistic. This is suitable for light nuclei.
	The standard POTCARs are scalar-relativistic and account partially for relativistic effects.		The standard POTCARs are scalar-relativistic and account partially for relativistic effects.

Csheldon: /* References */

2025-03-19T09:44:02Z

References

← Older revision		Revision as of 09:44, 19 March 2025
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	==References==		==References==

	[[Category:Howto]][[Category:NMR]][[Category:Linear response~~]][[Category:Chemical shifts~~]]		[[Category:Howto]][[Category:NMR]][[Category:Linear response]]

Csheldon at 09:43, 19 March 2025

2025-03-19T09:43:49Z

← Older revision		Revision as of 09:43, 19 March 2025
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	==References==		==References==

	~~<!--~~ [[Category:Howto]][[Category:NMR]][[Category:Linear response]][[Category:Chemical shifts]] ~~--!>~~		[[Category:Howto]][[Category:NMR]][[Category:Linear response]][[Category:Chemical shifts]]

Csheldon: Csheldon moved page Construction:NMR to Calculating the chemical shieldings

2025-03-10T09:31:05Z

Csheldon moved page Construction:NMR to Calculating the chemical shieldings

← Older revision	Revision as of 09:31, 10 March 2025
(No difference)

Csheldon: /* Energy cutoff tests */

2025-03-07T15:38:09Z

Energy cutoff tests

← Older revision		Revision as of 15:38, 7 March 2025
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	{{TAGBL\|NLSPLINE}} = .TRUE.		{{TAGBL\|NLSPLINE}} = .TRUE.

	Script to loop through {{TAG\|ENCUT}} from 400 eV to ~~600~~ eV:		Script to loop through {{TAG\|ENCUT}} from 400 eV to 800 eV:
	<pre>		<pre>
	for a in 400 500 600 700 800		for a in 400 500 600 700 800

Csheldon: /* Energetic break criterion tests */

2025-03-07T15:29:49Z

Energetic break criterion tests

← Older revision		Revision as of 15:29, 7 March 2025
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	'''INCAR.nmr'''		'''INCAR.nmr'''
	{{TAGBL\|PREC}} = Accurate		{{TAGBL\|PREC}} = Accurate
	{{TAGBL\|ENCUT}} = ~~600~~.0		{{TAGBL\|ENCUT}} = 400.0
	{{TAGBL\|EDIFF}} = 1E-8		{{TAGBL\|EDIFF}} = 1E-4
	{{TAGBL\|ISMEAR}} = 0; {{TAGBL\|SIGMA}} = 0.1		{{TAGBL\|ISMEAR}} = 0; {{TAGBL\|SIGMA}} = 0.1
	{{TAGBL\|LREAL}} = A		{{TAGBL\|LREAL}} = A

Csheldon: /* Energy cutoff tests */

2025-03-07T15:29:38Z

Energy cutoff tests

← Older revision		Revision as of 15:29, 7 March 2025
Line 110:		Line 110:
	'''INCAR.nmr'''		'''INCAR.nmr'''
	{{TAGBL\|PREC}} = Accurate		{{TAGBL\|PREC}} = Accurate
	{{TAGBL\|ENCUT}} = ~~600~~.0		{{TAGBL\|ENCUT}} = 400.0
	{{TAGBL\|EDIFF}} = 1E-8		{{TAGBL\|EDIFF}} = 1E-8
	{{TAGBL\|ISMEAR}} = 0; {{TAGBL\|SIGMA}} = 0.1		{{TAGBL\|ISMEAR}} = 0; {{TAGBL\|SIGMA}} = 0.1

Csheldon: /* Energy cutoff tests */

2025-03-07T15:29:29Z

Energy cutoff tests

← Older revision		Revision as of 15:29, 7 March 2025
Line 109:		Line 109:
	Initial {{TAGBL\|INCAR}}:		Initial {{TAGBL\|INCAR}}:
	'''INCAR.nmr'''		'''INCAR.nmr'''
	~~<pre>~~		{{TAGBL\|PREC}} = Accurate
	PREC = Accurate		{{TAGBL\|ENCUT}} = 600.0
	ENCUT = ~~400~~		{{TAGBL\|EDIFF}} = 1E-8
	EDIFF = 1E-6		{{TAGBL\|ISMEAR}} = 0; {{TAGBL\|SIGMA}} = 0.1
	ISMEAR = 0; SIGMA = 0.01		{{TAGBL\|LREAL}} = A
	~~</pre>~~		{{TAGBL\|LCHIMAG}} = .TRUE.
			{{TAGBL\|DQ}} = 0.001
			{{TAGBL\|ICHIBARE}} = 1
			{{TAGBL\|LNMR_SYM_RED}} = .TRUE.
			{{TAGBL\|NLSPLINE}} = .TRUE.

	Script to loop through {{TAG\|ENCUT}} from 400 eV to 600 eV:		Script to loop through {{TAG\|ENCUT}} from 400 eV to 600 eV:

Csheldon at 15:28, 7 March 2025

2025-03-07T15:28:22Z

← Older revision		Revision as of 15:28, 7 March 2025
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	The chemical shielding tensor ''σ'' is the relation between the induced and external magnetic fields and describes how much the electrons shield the nuclei from an external field. The absolute chemical shielding is calculated by linear response using {{TAG\|LCHIMAG}} {{Cite\|pickard:prb:2001}}{{Cite\|yates:prb:2007}}. The chemical shielding is directly related to the chemical shift ''δ'' recorded in nuclear magnetic resonance (NMR), cf. [[:Category:NMR\|NMR category page]] and {{TAG\|LCHIMAG}} page for details, and, indirectly, to the resonance frequency. The theory is covered in the [[:Category:NMR\|NMR category page]] and {{TAG\|LCHIMAG}} page.		The chemical shielding tensor ''σ'' is the relation between the induced and external magnetic fields and describes how much the electrons shield the nuclei from an external field. The absolute chemical shielding is calculated by linear response using {{TAG\|LCHIMAG}} {{Cite\|pickard:prb:2001}}{{Cite\|yates:prb:2007}}. The chemical shielding is directly related to the chemical shift ''δ'' recorded in nuclear magnetic resonance (NMR), cf. [[:Category:NMR\|NMR category page]] and {{TAG\|LCHIMAG}} page for details, and, indirectly, to the resonance frequency. The theory is covered in the [[:Category:NMR\|NMR category page]] and {{TAG\|LCHIMAG}} page.
			{{NB\|warning\|The chemical shifts are calculated from the orbital magnetic response under the assumption that the system is an insulator. Smearing schemes intended for metals can generate nonsense.}}

	==Step-by-step instructions==		==Step-by-step instructions==

← Older revision		Revision as of 15:29, 7 March 2025
Line 55:		Line 55:
	'''INCAR.nmr'''		'''INCAR.nmr'''
	{{TAGBL\|PREC}} = Accurate		{{TAGBL\|PREC}} = Accurate
	{{TAGBL\|ENCUT}} = ~~600~~.0		{{TAGBL\|ENCUT}} = 400.0
	{{TAGBL\|EDIFF}} = 1E-8		{{TAGBL\|EDIFF}} = 1E-4
	{{TAGBL\|ISMEAR}} = 0; {{TAGBL\|SIGMA}} = 0.1		{{TAGBL\|ISMEAR}} = 0; {{TAGBL\|SIGMA}} = 0.1
	{{TAGBL\|LREAL}} = A		{{TAGBL\|LREAL}} = A

← Older revision		Revision as of 15:29, 7 March 2025
Line 110:		Line 110:
	'''INCAR.nmr'''		'''INCAR.nmr'''
	{{TAGBL\|PREC}} = Accurate		{{TAGBL\|PREC}} = Accurate
	{{TAGBL\|ENCUT}} = ~~600~~.0		{{TAGBL\|ENCUT}} = 400.0
	{{TAGBL\|EDIFF}} = 1E-8		{{TAGBL\|EDIFF}} = 1E-8
	{{TAGBL\|ISMEAR}} = 0; {{TAGBL\|SIGMA}} = 0.1		{{TAGBL\|ISMEAR}} = 0; {{TAGBL\|SIGMA}} = 0.1

← Older revision		Revision as of 15:29, 7 March 2025
Line 109:		Line 109:
	Initial {{TAGBL\|INCAR}}:		Initial {{TAGBL\|INCAR}}:
	'''INCAR.nmr'''		'''INCAR.nmr'''
	~~<pre>~~		{{TAGBL\|PREC}} = Accurate
	PREC = Accurate		{{TAGBL\|ENCUT}} = 600.0
	ENCUT = ~~400~~		{{TAGBL\|EDIFF}} = 1E-8
	EDIFF = 1E-6		{{TAGBL\|ISMEAR}} = 0; {{TAGBL\|SIGMA}} = 0.1
	ISMEAR = 0; SIGMA = 0.01		{{TAGBL\|LREAL}} = A
	~~</pre>~~		{{TAGBL\|LCHIMAG}} = .TRUE.
			{{TAGBL\|DQ}} = 0.001
			{{TAGBL\|ICHIBARE}} = 1
			{{TAGBL\|LNMR_SYM_RED}} = .TRUE.
			{{TAGBL\|NLSPLINE}} = .TRUE.

	Script to loop through {{TAG\|ENCUT}} from 400 eV to 600 eV:		Script to loop through {{TAG\|ENCUT}} from 400 eV to 600 eV: