Alpha-SiO2 - Revision history

Karsai: /* Download */

2019-11-14T13:16:11Z

Download

← Older revision		Revision as of 13:16, 14 November 2019
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	== Download ==		== Download ==
	[~~http~~:~~//www.vasp.at/vasp-workshop/examples/~~SiO2_NMR.tgz SiO2_NMR.tgz]		[[Media:SiO2_NMR.tgz\| SiO2_NMR.tgz]]

	----		----
	~~[[VASP_example_calculations\|To the list of examples]] or to the [[The_VASP_Manual\|main page]]~~

	[[Category:Examples]]		[[Category:Examples]]

Karsai at 14:58, 14 March 2017

2017-03-14T14:58:50Z

← Older revision		Revision as of 14:58, 14 March 2017
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	[http://www.vasp.at/vasp-workshop/examples/SiO2_NMR.tgz SiO2_NMR.tgz]		[http://www.vasp.at/vasp-workshop/examples/SiO2_NMR.tgz SiO2_NMR.tgz]

	~~== Used INCAR Tags ==~~
	{{TAG\|DQ}},{{TAG\|EDIFF}},{{TAG\|EDIFFG}},{{TAG\|EMAX}},{{TAG\|EMIN}},{{TAG\|ENCUT}},{{TAG\|GGA}},{{TAG\|IALGO}},{{TAG\|IBRION}},{{TAG\|ICHARG}},{{TAG\|ICHIBARE}},{{TAG\|INIWAV}},{{TAG\|ISIF}},{{TAG\|ISMEAR}},{{TAG\|ISPIN}},{{TAG\|ISTART}},{{TAG\|ISYM}},{{TAG\|LCHIMAG}},{{TAG\|LEFG}},{{TAG\|LNMR_SYM_RED}},{{TAG\|LREAL}},{{TAG\|LWAVE}},{{TAG\|NBANDS}},{{TAG\|NEDOS}},{{TAG\|NLSPLINE}},{{TAG\|NSW}},{{TAG\|POTIM}},{{TAG\|PREC}},{{TAG\|QUAD_EFG}},{{TAG\|SYSTEM}}
	----		----
	[[VASP_example_calculations\|To the list of examples]] or to the [[The_VASP_Manual\|main page]]		[[VASP_example_calculations\|To the list of examples]] or to the [[The_VASP_Manual\|main page]]

	[[Category:Examples]]		[[Category:Examples]]

Karsai at 13:39, 14 March 2017

2017-03-14T13:39:53Z

← Older revision		Revision as of 13:39, 14 March 2017
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	{{TAGBL\|SYSTEM}} = Si O2		{{TAGBL\|SYSTEM}} = Si O2

	{{TAGBL\|GGA}} = PE		{{TAGBL\|GGA}} = PE
	{{TAGBL\|ISTART}} = 1		{{TAGBL\|ISTART}} = 1
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	Electronic minimisation		Electronic minimisation
	{{TAGBL\|IALGO}} = 38		{{TAGBL\|IALGO}} = 38

	{{TAGBL\|LWAVE}} = .TRUE.		{{TAGBL\|LWAVE}} = .TRUE.

	{{TAGBL\|EMIN}} = -20.0		{{TAGBL\|EMIN}} = -20.0
	{{TAGBL\|EMAX}} = 10.0		{{TAGBL\|EMAX}} = 10.0
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	{{TAGBL\|ISMEAR}} = 0; SIGMA= 0.1 # no fancy smearings, SIGMA sufficiently small		{{TAGBL\|ISMEAR}} = 0; SIGMA= 0.1 # no fancy smearings, SIGMA sufficiently small
	{{TAGBL\|EDIFF}} = 1E-9 # you'd need much smaller EDIFFs.		{{TAGBL\|EDIFF}} = 1E-9 # you'd need much smaller EDIFFs.

	{{TAGBL\|LCHIMAG}} = .TRUE. # to switch on linear response for chemical shifts		{{TAGBL\|LCHIMAG}} = .TRUE. # to switch on linear response for chemical shifts
	{{TAGBL\|DQ}} = 0.001 # often the default is sufficient		{{TAGBL\|DQ}} = 0.001 # often the default is sufficient

Karsai at 13:39, 14 March 2017

2017-03-14T13:39:18Z

← Older revision		Revision as of 13:39, 14 March 2017
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	*{{TAG\|INCAR}}		*{{TAG\|INCAR}}
	~~<pre>~~
	{{TAGBL\|SYSTEM}} = Si O2		{{TAGBL\|SYSTEM}} = Si O2

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	{{TAGBL\|LREAL}} = A # helps for speed for large systems, not needed		{{TAGBL\|LREAL}} = A # helps for speed for large systems, not needed
	{{TAGBL\|NBANDS}} = 30 # to safe memory, ??? = NELECT/2		{{TAGBL\|NBANDS}} = 30 # to safe memory, ??? = NELECT/2
	~~</pre>~~

	*{{TAG\|KPOINTS}}		*{{TAG\|KPOINTS}}

Karsai at 13:39, 14 March 2017

2017-03-14T13:39:02Z

← Older revision		Revision as of 13:39, 14 March 2017
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	*{{TAG\|INCAR}}		*{{TAG\|INCAR}}
	<pre>		<pre>
	SYSTEM = Si O2		{{TAGBL\|SYSTEM}} = Si O2

	GGA = PE		{{TAGBL\|GGA}} = PE
	ISTART = 1		{{TAGBL\|ISTART}} = 1
	ICHARG = 0		{{TAGBL\|ICHARG}} = 0
	INIWAV = 1		{{TAGBL\|INIWAV}} = 1
	LREAL = AUTO		{{TAGBL\|LREAL}} = AUTO
	ISYM = 2		{{TAGBL\|ISYM}} = 2
	ISPIN = 1		{{TAGBL\|ISPIN}} = 1

	Ionic minimisation		Ionic minimisation
	NSW = 0		{{TAGBL\|NSW}} = 0
	ISIF = 2		{{TAGBL\|ISIF}} = 2
	IBRION = 2		{{TAGBL\|IBRION}} = 2
	# EDIFFG = -2E-2		# {{TAGBL\|EDIFFG}} = -2E-2
	POTIM = 0.1		{{TAGBL\|POTIM}} = 0.1

	Electronic minimisation		Electronic minimisation
	IALGO = 38		{{TAGBL\|IALGO}} = 38

	LWAVE = .TRUE.		{{TAGBL\|LWAVE}} = .TRUE.

	EMIN = -20.0		{{TAGBL\|EMIN}} = -20.0
	EMAX = 10.0		{{TAGBL\|EMAX}} = 10.0
	NEDOS = 1601		{{TAGBL\|NEDOS}} = 1601

	EFG Calculation		EFG Calculation
	LEFG = .TRUE.		{{TAGBL\|LEFG}} = .TRUE.
	QUAD_EFG = 0.0 25.5		{{TAGBL\|QUAD_EFG}} = 0.0 25.5

	Chemical Shift		Chemical Shift
	PREC = Normal # nice		{{TAGBL\|PREC}} = Normal # nice
	ENCUT = 400.0 # typically higher cutoffs than usual are needed		{{TAGBL\|ENCUT}} = 400.0 # typically higher cutoffs than usual are needed
	ISMEAR = 0; SIGMA= 0.1 # no fancy smearings, SIGMA sufficiently small		{{TAGBL\|ISMEAR}} = 0; SIGMA= 0.1 # no fancy smearings, SIGMA sufficiently small
	EDIFF = 1E-9 # you'd need much smaller EDIFFs.		{{TAGBL\|EDIFF}} = 1E-9 # you'd need much smaller EDIFFs.

	LCHIMAG = .TRUE. # to switch on linear response for chemical shifts		{{TAGBL\|LCHIMAG}} = .TRUE. # to switch on linear response for chemical shifts
	DQ = 0.001 # often the default is sufficient		{{TAGBL\|DQ}} = 0.001 # often the default is sufficient
	ICHIBARE = 1 # often the default is sufficient		{{TAGBL\|ICHIBARE}} = 1 # often the default is sufficient
	LNMR_SYM_RED = .TRUE. # be on the safe side		{{TAGBL\|LNMR_SYM_RED}} = .TRUE. # be on the safe side
	NLSPLINE = .TRUE. # only needed if LREAL is NOT set.		{{TAGBL\|NLSPLINE}} = .TRUE. # only needed if LREAL is NOT set.
	LREAL = A # helps for speed for large systems, not needed		{{TAGBL\|LREAL}} = A # helps for speed for large systems, not needed
	NBANDS = 30 # to safe memory, ??? = NELECT/2		{{TAGBL\|NBANDS}} = 30 # to safe memory, ??? = NELECT/2
	</pre>		</pre>

Karsai at 12:16, 24 February 2017

2017-02-24T12:16:01Z

← Older revision		Revision as of 12:16, 24 February 2017
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	The calculated shielding tensors components can be compared to the ones obtained by Profeta ''et al.''		The calculated shielding tensors components can be compared to the ones obtained by Profeta ''et al.''

	*INCAR		*{{TAG\|INCAR}}
	<pre>		<pre>
	SYSTEM = Si O2		SYSTEM = Si O2
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	</pre>		</pre>

	*KPOINTS		*{{TAG\|KPOINTS}}
	<pre>		<pre>
	automatic mesh		automatic mesh
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	</pre>		</pre>

	*POSCAR		*{{TAG\|POSCAR}}
	<pre>		<pre>
	O2 Si1		O2 Si1
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	[http://www.vasp.at/vasp-workshop/examples/SiO2_NMR.tgz SiO2_NMR.tgz]		[http://www.vasp.at/vasp-workshop/examples/SiO2_NMR.tgz SiO2_NMR.tgz]

			== Used INCAR Tags ==
			{{TAG\|DQ}},{{TAG\|EDIFF}},{{TAG\|EDIFFG}},{{TAG\|EMAX}},{{TAG\|EMIN}},{{TAG\|ENCUT}},{{TAG\|GGA}},{{TAG\|IALGO}},{{TAG\|IBRION}},{{TAG\|ICHARG}},{{TAG\|ICHIBARE}},{{TAG\|INIWAV}},{{TAG\|ISIF}},{{TAG\|ISMEAR}},{{TAG\|ISPIN}},{{TAG\|ISTART}},{{TAG\|ISYM}},{{TAG\|LCHIMAG}},{{TAG\|LEFG}},{{TAG\|LNMR_SYM_RED}},{{TAG\|LREAL}},{{TAG\|LWAVE}},{{TAG\|NBANDS}},{{TAG\|NEDOS}},{{TAG\|NLSPLINE}},{{TAG\|NSW}},{{TAG\|POTIM}},{{TAG\|PREC}},{{TAG\|QUAD_EFG}},{{TAG\|SYSTEM}}
	----		----
	[[VASP_example_calculations\|To the list of examples]] or to the [[The_VASP_Manual\|main page]]		[[VASP_example_calculations\|To the list of examples]] or to the [[The_VASP_Manual\|main page]]

	[[Category:Examples]]		[[Category:Examples]]

Karsai at 11:26, 24 February 2017

2017-02-24T11:26:24Z

← Older revision		Revision as of 11:26, 24 February 2017
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	ICHIBARE = 1 # often the default is sufficient		ICHIBARE = 1 # often the default is sufficient
	LNMR_SYM_RED = .TRUE. # be on the safe side		LNMR_SYM_RED = .TRUE. # be on the safe side
	~~NSLPLINE~~ = .TRUE. # only needed if LREAL is NOT set.		NLSPLINE = .TRUE. # only needed if LREAL is NOT set.
	LREAL = A # helps for speed for large systems, not needed		LREAL = A # helps for speed for large systems, not needed
	NBANDS = 30 # to safe memory, ??? = NELECT/2		NBANDS = 30 # to safe memory, ??? = NELECT/2

Xavier at 18:00, 1 September 2016

2016-09-01T18:00:57Z

← Older revision		Revision as of 18:00, 1 September 2016
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	== Download ==		== Download ==
	[http://www.vasp.at/vasp-workshop/examples/~~Ni111clean_400eV~~.tgz ~~Ni111clean_400eV~~.tgz]		[http://www.vasp.at/vasp-workshop/examples/SiO2_NMR.tgz SiO2_NMR.tgz]

	----		----

Xavier at 18:45, 31 August 2016

2016-08-31T18:45:59Z

← Older revision		Revision as of 18:45, 31 August 2016
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	''<u>Exercise :</u>'' Determine the <sup>17</sup>O C<sub>q</sub> value and the Si and O schieldings.		''<u>Exercise :</u>'' Determine the <sup>17</sup>O C<sub>q</sub> value and the Si and O schieldings.

	alpha-SiO<sub>2</sub> crystallizes in the trigonal P3<sub>1</sub>2 space group.		α-SiO<sub>2</sub> crystallizes in the trigonal P3<sub>1</sub>2 space group.

	a = b = 4.604 Å; c = 5.207 Å		a = b = 4.604 Å; c = 5.207 Å
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	α = β = 90°; γ = 120°		α = β = 90°; γ = 120°

	The unit cell contains two independent atoms (1 Si and 1 O) with 3 formula units (SiO<sub>2</sub>) per unit cell (Z=3). SiO<sub>4</sub> tetrahedron units are linked ~~each others~~ by corner sharing.		The unit cell contains two independent atoms (1 Si and 1 O) with 3 formula units (SiO<sub>2</sub>) per unit cell (Z=3). SiO<sub>4</sub> tetrahedron units are linked together by corner sharing.

	In this exercise one wants first to calculate the EFG tensor components of <sup>17</sup>O.		In this exercise one wants first to calculate the EFG tensor components of <sup>17</sup>O.
	This is very fast task calculated at the end of the first SCF calculation (ground state property).		This is very fast task calculated at the end of the first SCF calculation (ground state property).
	The experimental values for the Cq is 5.19 MHz. The nuclear quadrupolar momentum used to transform EFG in C<sub>q</sub> is Q = 2.55 10<sup>-30</sup> m<sup>2</sup>		The experimental values for the C<sub>q</sub> is 5.19 MHz. The nuclear quadrupolar momentum used to transform EFG in C<sub>q</sub> is Q = 2.55 10<sup>-30</sup> m<sup>2</sup>
	(see the paper of Profeta ''et al.'' (http://pubs.acs.org/doi/abs/10.1021/ja027124r)		(see the paper of Profeta ''et al.'' (http://pubs.acs.org/doi/abs/10.1021/ja027124r)
	(Silicon has a 1/2 nuclear spin, so Q is zero)		(Silicon has a 1/2 nuclear spin, so Q is zero)

Xavier at 18:30, 31 August 2016

2016-08-31T18:30:39Z

← Older revision		Revision as of 18:30, 31 August 2016
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	''<u>Exercise :</u>'' Determine the <sup>17</sup>O C<sub>q</sub> value and the Si and O schieldings.		''<u>Exercise :</u>'' Determine the <sup>17</sup>O C<sub>q</sub> value and the Si and O schieldings.

			alpha-SiO<sub>2</sub> crystallizes in the trigonal P3<sub>1</sub>2 space group.

			a = b = 4.604 Å; c = 5.207 Å

			α = β = 90°; γ = 120°

			The unit cell contains two independent atoms (1 Si and 1 O) with 3 formula units (SiO<sub>2</sub>) per unit cell (Z=3). SiO<sub>4</sub> tetrahedron units are linked each others by corner sharing.

			In this exercise one wants first to calculate the EFG tensor components of <sup>17</sup>O.
			This is very fast task calculated at the end of the first SCF calculation (ground state property).
			The experimental values for the Cq is 5.19 MHz. The nuclear quadrupolar momentum used to transform EFG in C<sub>q</sub> is Q = 2.55 10<sup>-30</sup> m<sup>2</sup>
			(see the paper of Profeta ''et al.'' (http://pubs.acs.org/doi/abs/10.1021/ja027124r)
			(Silicon has a 1/2 nuclear spin, so Q is zero)

			In a second step one wants to calculate the shielding parameters for Si and O. This is done using the linear response using the GIPAW formalism.
			As the calculation is quite time consuming, only very few k-points and small ENCUT are used with standard PAW data sets.
			The calculated shielding tensors components can be compared to the ones obtained by Profeta ''et al.''

	*INCAR		*INCAR

← Older revision		Revision as of 13:39, 14 March 2017
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	{{TAGBL\|SYSTEM}} = Si O2		{{TAGBL\|SYSTEM}} = Si O2

	{{TAGBL\|GGA}} = PE		{{TAGBL\|GGA}} = PE
	{{TAGBL\|ISTART}} = 1		{{TAGBL\|ISTART}} = 1
Line 40:		Line 39:
	Electronic minimisation		Electronic minimisation
	{{TAGBL\|IALGO}} = 38		{{TAGBL\|IALGO}} = 38

	{{TAGBL\|LWAVE}} = .TRUE.		{{TAGBL\|LWAVE}} = .TRUE.

	{{TAGBL\|EMIN}} = -20.0		{{TAGBL\|EMIN}} = -20.0
	{{TAGBL\|EMAX}} = 10.0		{{TAGBL\|EMAX}} = 10.0
Line 56:		Line 53:
	{{TAGBL\|ISMEAR}} = 0; SIGMA= 0.1 # no fancy smearings, SIGMA sufficiently small		{{TAGBL\|ISMEAR}} = 0; SIGMA= 0.1 # no fancy smearings, SIGMA sufficiently small
	{{TAGBL\|EDIFF}} = 1E-9 # you'd need much smaller EDIFFs.		{{TAGBL\|EDIFF}} = 1E-9 # you'd need much smaller EDIFFs.

	{{TAGBL\|LCHIMAG}} = .TRUE. # to switch on linear response for chemical shifts		{{TAGBL\|LCHIMAG}} = .TRUE. # to switch on linear response for chemical shifts
	{{TAGBL\|DQ}} = 0.001 # often the default is sufficient		{{TAGBL\|DQ}} = 0.001 # often the default is sufficient

← Older revision		Revision as of 13:39, 14 March 2017
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	*{{TAG\|INCAR}}		*{{TAG\|INCAR}}
	~~<pre>~~
	{{TAGBL\|SYSTEM}} = Si O2		{{TAGBL\|SYSTEM}} = Si O2

Line 64:		Line 64:
	{{TAGBL\|LREAL}} = A # helps for speed for large systems, not needed		{{TAGBL\|LREAL}} = A # helps for speed for large systems, not needed
	{{TAGBL\|NBANDS}} = 30 # to safe memory, ??? = NELECT/2		{{TAGBL\|NBANDS}} = 30 # to safe memory, ??? = NELECT/2
	~~</pre>~~

	*{{TAG\|KPOINTS}}		*{{TAG\|KPOINTS}}