Category:Linear response - Revision history

Csheldon: /* Tutorials */

2025-05-28T13:09:38Z

Tutorials

← Older revision		Revision as of 13:09, 28 May 2025
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	== Tutorials ==		== Tutorials ==
	*Tutorial for [https://vasp.at/tutorials/latest/response/part1/ static and frequency-dependent response calculations].		*Tutorial for [https://vasp.at/tutorials/latest/response/part1/ static and frequency-dependent response calculations].
			<!--*Tutorial for [https://vasp.at/tutorials/latest/xas/part1 SCH XAS calculations].
			*Tutorial for [https://vasp.at/tutorials/latest/xas/part2 BSE XAS calculations].
			*Tutorial for [https://vasp.at/tutorials/latest/nmr/part1 chemical shielding calculations].
			*Tutorial for [https://vasp.at/tutorials/latest/nmr/part2 coupling constants and two-center correction calculations].
			*Tutorial for [https://vasp.at/tutorials/latest/nmr/part3 NICS and current calculations].
			*Tutorial for [https://vasp.at/tutorials/latest/phonon/ phonon calculations]. -->

	[[Category:VASP\|Linear response]]		[[Category:VASP\|Linear response]]

Csheldon at 13:05, 28 May 2025

2025-05-28T13:05:49Z

← Older revision		Revision as of 13:05, 28 May 2025
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	*[[SCH calculations\|XAS from the supercell core-hole method]]		*[[SCH calculations\|XAS from the supercell core-hole method]]
	*[[Bethe-Salpeter equation for core excitations\|XAS from the Bethe-Salpeter equation]]		*[[Bethe-Salpeter equation for core excitations\|XAS from the Bethe-Salpeter equation]]

			== Tutorials ==
			*Tutorial for [https://vasp.at/tutorials/latest/response/part1/ static and frequency-dependent response calculations].

	[[Category:VASP\|Linear response]]		[[Category:VASP\|Linear response]]

Csheldon: /* X-ray absorption spectroscopy (XAS) */

2025-05-28T11:56:42Z

X-ray absorption spectroscopy (XAS)

← Older revision		Revision as of 11:56, 28 May 2025
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	== X-ray absorption spectroscopy (XAS) ==		== X-ray absorption spectroscopy (XAS) ==

	Another case of interest is the absorption of electromagnetic radiation by core electrons as measured experimentally in [[:Category:XAS\| X-ray absorption spectroscopy (XAS)]]. The absorption spectra can be found from the imaginary part of the frequency-dependent dielectric function. Two methods for calculating XAS are available in VASP: the supercell core-hole (SCH) method and the Bethe-Salpeter equation (BSE). Both methods are capable of including the excitonic effects in the spectra. In SCH these effects are included at the DFT level, while the BSE approach relies on the many-body perturbation theory. ~~Find the~~ comparison of the two approaches [[:Category:XAS\|~~here~~]].		Another case of interest is the absorption of electromagnetic radiation by core electrons as measured experimentally in [[:Category:XAS\| X-ray absorption spectroscopy (XAS)]]. The absorption spectra can be found from the imaginary part of the frequency-dependent dielectric function. Two methods for calculating XAS are available in VASP: the supercell core-hole (SCH) method and the Bethe-Salpeter equation (BSE). Both methods are capable of including the excitonic effects in the spectra. In SCH these effects are included at the DFT level, while the BSE approach relies on the many-body perturbation theory. A comparison of the two approaches is given in the [[:Category:XAS\|XAS category page]].

	== Nuclear magnetic resonance (NMR) ==		== Nuclear magnetic resonance (NMR) ==

Ftran at 10:00, 28 February 2025

2025-02-28T10:00:53Z

← Older revision		Revision as of 10:00, 28 February 2025
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	=== Dielectric tensor ===		=== Dielectric tensor ===
	The static dielectric tensor can be computed by finite differences {{TAG\|LCALCEPS}} of the polarization with respect to a finite external electric field or by using density functional perturbation theory {{TAG\|LEPSILON}}.		The static dielectric tensor can be computed by finite differences {{TAG\|LCALCEPS}} of the polarization with respect to a finite external electric field or by using density functional perturbation theory {{TAG\|LEPSILON}}.
	Both {{TAG\|LEPSILON}} or {{TAG\|LCALCEPS}} yield the same converged results for the dielectric tensor, however, the former can only be used for local or semi-local exchange-correlation functionals and applies to both semiconductors and metals while the second can be used for ~~[[:Category: Meta-GGA~~\|~~meta-GGA]]~~ or [[:Category: Hybrid functionals\|hybrid]] but [[EFIELD_PEAD\|only for systems with a gap]].		Both {{TAG\|LEPSILON}} or {{TAG\|LCALCEPS}} yield the same converged results for the dielectric tensor, however, the former can only be used for local or semi-local exchange-correlation functionals and applies to both semiconductors and metals while the second can be used for {{TAG\|METAGGA}} or [[:Category: Hybrid functionals\|hybrid]] but [[EFIELD_PEAD\|only for systems with a gap]].

	=== Born effective charges ===		=== Born effective charges ===

Csheldon: Undo revision 28668 by Csheldon (talk)

2025-02-24T14:52:13Z

Undo revision 28668 by Csheldon (talk)

← Older revision		Revision as of 14:52, 24 February 2025
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	*[[Bethe-Salpeter equation for core excitations\|XAS from the Bethe-Salpeter equation]]		*[[Bethe-Salpeter equation for core excitations\|XAS from the Bethe-Salpeter equation]]

	[[Category:Linear response~~]][[Category:NMR]][[Category:Howto~~]]		[[Category:VASP\|Linear response]]

Csheldon at 14:51, 24 February 2025

2025-02-24T14:51:57Z

← Older revision		Revision as of 14:51, 24 February 2025
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	*[[Bethe-Salpeter equation for core excitations\|XAS from the Bethe-Salpeter equation]]		*[[Bethe-Salpeter equation for core excitations\|XAS from the Bethe-Salpeter equation]]

	[[Category:~~VASP\|~~Linear response]]		[[Category:Linear response]][[Category:NMR]][[Category:Howto]]

Tal: /* X-ray absorption spectroscopy (XAS) */

2025-02-21T10:14:00Z

X-ray absorption spectroscopy (XAS)

← Older revision		Revision as of 10:14, 21 February 2025
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	== X-ray absorption spectroscopy (XAS) ==		== X-ray absorption spectroscopy (XAS) ==

	Another case of interest is the absorption of electromagnetic radiation by core electrons as measured experimentally in [[:Category:XAS\| X-ray absorption spectroscopy (XAS)]]. The absorption spectra can be found from the imaginary part of the frequency-dependent dielectric function. Two methods for calculating XAS are available in VASP: the supercell core-hole (SCH) method and the Bethe-Salpeter equation (BSE). Both methods are capable of including the excitonic effects in the spectra~~, but in~~ the ~~case of SCH it is done via~~ DFT, while the BSE approach relies on the many-body perturbation theory. Find the comparison of the two approaches [[:Category:XAS\|here]].		Another case of interest is the absorption of electromagnetic radiation by core electrons as measured experimentally in [[:Category:XAS\| X-ray absorption spectroscopy (XAS)]]. The absorption spectra can be found from the imaginary part of the frequency-dependent dielectric function. Two methods for calculating XAS are available in VASP: the supercell core-hole (SCH) method and the Bethe-Salpeter equation (BSE). Both methods are capable of including the excitonic effects in the spectra. In SCH these effects are included at the DFT level, while the BSE approach relies on the many-body perturbation theory. Find the comparison of the two approaches [[:Category:XAS\|here]].

	== Nuclear magnetic resonance (NMR) ==		== Nuclear magnetic resonance (NMR) ==

Tal: /* X-ray absorption spectroscopy (XAS) */

2025-02-21T10:11:53Z

X-ray absorption spectroscopy (XAS)

← Older revision		Revision as of 10:11, 21 February 2025
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	== X-ray absorption spectroscopy (XAS) ==		== X-ray absorption spectroscopy (XAS) ==

	Another case of interest is the absorption of electromagnetic radiation by core electrons as measured experimentally in [[:Category:XAS\| X-ray absorption spectroscopy (XAS)]]. The absorption spectra can found from the imaginary part of the frequency-dependent dielectric function. Two methods for calculating XAS are available in VASP: the supercell core-hole (SCH) method and the Bethe-Salpeter equation (BSE). Both methods are capable of including the excitonic effects in the spectra, but in the case of SCH it is done via DFT, while the BSE approach relies on the many-body perturbation theory. Find the comparison of the two approaches [[:Category:XAS\|here]].		Another case of interest is the absorption of electromagnetic radiation by core electrons as measured experimentally in [[:Category:XAS\| X-ray absorption spectroscopy (XAS)]]. The absorption spectra can be found from the imaginary part of the frequency-dependent dielectric function. Two methods for calculating XAS are available in VASP: the supercell core-hole (SCH) method and the Bethe-Salpeter equation (BSE). Both methods are capable of including the excitonic effects in the spectra, but in the case of SCH it is done via DFT, while the BSE approach relies on the many-body perturbation theory. Find the comparison of the two approaches [[:Category:XAS\|here]].

	== Nuclear magnetic resonance (NMR) ==		== Nuclear magnetic resonance (NMR) ==

Tal: /* How to */

2025-02-21T10:08:17Z

How to

← Older revision		Revision as of 10:08, 21 February 2025
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	*[[SCH calculations\|XAS from the supercell core-hole method]]		*[[SCH calculations\|XAS from the supercell core-hole method]]
			*[[Bethe-Salpeter equation for core excitations\|XAS from the Bethe-Salpeter equation]]

	[[Category:VASP\|Linear response]]		[[Category:VASP\|Linear response]]

Tal: /* X-ray absorption spectroscopy (XAS) */

2025-02-21T10:07:24Z

X-ray absorption spectroscopy (XAS)

← Older revision		Revision as of 10:07, 21 February 2025
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	== X-ray absorption spectroscopy (XAS) ==		== X-ray absorption spectroscopy (XAS) ==

	Another case of interest is the absorption of electromagnetic radiation by core electrons as measured experimentally in [[:Category:XAS\| X-ray absorption spectroscopy (XAS)]]. ~~This is obtained~~ from the frequency-dependent dielectric function ~~with~~ the ~~particularity that~~ core ~~electrons~~ are ~~explicitly included~~ in the ~~calculation~~.		Another case of interest is the absorption of electromagnetic radiation by core electrons as measured experimentally in [[:Category:XAS\| X-ray absorption spectroscopy (XAS)]]. The absorption spectra can found from the imaginary part of the frequency-dependent dielectric function. Two methods for calculating XAS are available in VASP: the supercell core-hole (SCH) method and the Bethe-Salpeter equation (BSE). Both methods are capable of including the excitonic effects in the spectra, but in the case of SCH it is done via DFT, while the BSE approach relies on the many-body perturbation theory. Find the comparison of the two approaches [[:Category:XAS\|here]].
	~~The~~ [[XAS ~~theory~~\|~~theory page~~]] ~~describes the implementation details within the PAW method and the relevant literature~~.

	== Nuclear magnetic resonance (NMR) ==		== Nuclear magnetic resonance (NMR) ==

← Older revision		Revision as of 10:08, 21 February 2025
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	*[[SCH calculations\|XAS from the supercell core-hole method]]		*[[SCH calculations\|XAS from the supercell core-hole method]]
			*[[Bethe-Salpeter equation for core excitations\|XAS from the Bethe-Salpeter equation]]

	[[Category:VASP\|Linear response]]		[[Category:VASP\|Linear response]]