How to analyse excitons - Revision history

FulvioPaleari: /* Sort the excitonic eigenvalues */

2025-11-24T18:15:39Z

Sort the excitonic eigenvalues

← Older revision		Revision as of 18:15, 24 November 2025
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	==Sort the excitonic eigenvalues==		==Sort the excitonic eigenvalues==

	$ ypp -J 2D_WR_WC -e s 1		$ ypp -J 2D_WR_WC -e s -b 1

	We are sorting the excitons for the q-index = 1 (optical limit q=0).		We are sorting the excitons for the q-index = 1 (optical limit q=0).

Daniele: /* Calculate the exciton oscillator strenght and amplitude */

2025-03-30T09:30:19Z

Calculate the exciton oscillator strenght and amplitude

← Older revision		Revision as of 09:30, 30 March 2025
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	The first exciton is essentially done of only single particle transitions from VBM to CBM at K (last k-point of the grid).		The first exciton is essentially done of only single particle transitions from VBM to CBM at K (last k-point of the grid).

	'''Note: the transistion Energy reported in the weight file are Kohn-Sham energy difference and not Quasiparticle energies.'''		'''Note: the transistion Energy reported in the weight file are Kohn-Sham energy difference and not Quasiparticle energies.'''

Daniele: /* Calculate the exciton oscillator strenght and amplitude */

2025-03-30T09:30:02Z

Calculate the exciton oscillator strenght and amplitude

← Older revision		Revision as of 09:30, 30 March 2025
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	4.000000 5.000000 7.000000 1.000000 0.922086 4.401093		4.000000 5.000000 7.000000 1.000000 0.922086 4.401093

	The first exciton is essentially done of only single particle transitions from VBM to CBM at K (last k-point of the grid).		The first exciton is essentially done of only single particle transitions from VBM to CBM at K (last k-point of the grid).
			'''Note: the transistion Energy reported in the weight file are Kohn-Sham energy difference and not Quasiparticle energies.'''

	[[File:Amplitude_plot.png\|none\|600px\|]]		[[File:Amplitude_plot.png\|none\|600px\|]]

Daniele: /* Calculate the exciton oscillator strenght and amplitude */

2025-03-30T09:29:03Z

Calculate the exciton oscillator strenght and amplitude

← Older revision		Revision as of 09:29, 30 March 2025
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	4.000000 5.000000 7.000000 2.000000 0.922095 4.401093		4.000000 5.000000 7.000000 2.000000 0.922095 4.401093
	4.000000 5.000000 7.000000 1.000000 0.922086 4.401093		4.000000 5.000000 7.000000 1.000000 0.922086 4.401093

	The first exciton is essentially done of only single particle transitions from VBM to CBM at K (last k-point of the grid).		The first exciton is essentially done of only single particle transitions from VBM to CBM at K (last k-point of the grid).

Attacc: /* Plot electron/hole average density (only in Yambo 5.x) */

2021-03-26T08:53:20Z

Plot electron/hole average density (only in Yambo 5.x)

← Older revision		Revision as of 08:53, 26 March 2021
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	and choose the exciton you want to plot. The electron/hole average densities correspond to generalized valence/conduction orbitals for a given exciton. They are interesting in particular for molecular crystals because they allow to distinguishing charge-transfer exctions from Frenkel or Wannier ones, by looking the relative position of the electron/hole densities.		and choose the exciton you want to plot. The electron/hole average densities correspond to generalized valence/conduction orbitals for a given exciton. They are interesting in particular for molecular crystals because they allow to distinguishing charge-transfer exctions from Frenkel or Wannier ones, by looking the relative position of the electron/hole densities.
	For example see the electron/hole average density ~~calculate~~ in a Metal Organic Framework:		For example see the electron/hole average density calculated in a Metal Organic Framework (MOF) that contains azobenzene:

	[[File:Average electron hole.png\|center \|600px\|Yambo tutorial image]]		[[File:Average electron hole.png\|center \|600px\|Yambo tutorial image]]

	~~This~~ figure is taken from ref. <ref>Strongly Bound Excitons in Metal-Organic Framework MOF-5: A Many-Body Perturbation Theory Study, A. R. Kshirsagar et al., [https://doi.org/10.26434/chemrxiv.14034917.v1 preprint ChemRxiv]</ref>.		this figure is taken from ref. <ref>Strongly Bound Excitons in Metal-Organic Framework MOF-5: A Many-Body Perturbation Theory Study, A. R. Kshirsagar et al., [https://doi.org/10.26434/chemrxiv.14034917.v1 preprint ChemRxiv]</ref>.

	== Interpolate exciton dispersion (only in Yambo 5.x)==		== Interpolate exciton dispersion (only in Yambo 5.x)==

Attacc: /* Plot electron/hole average density (only in Yambo 5.x) */

2021-03-26T08:52:18Z

Plot electron/hole average density (only in Yambo 5.x)

← Older revision		Revision as of 08:52, 26 March 2021
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	For example see the electron/hole average density calculate in a Metal Organic Framework:		For example see the electron/hole average density calculate in a Metal Organic Framework:

	[[File:Average electron hole.png\|center \| ~~300px~~\|Yambo tutorial image]]		[[File:Average electron hole.png\|center \|600px\|Yambo tutorial image]]

	This figure is taken from ref. <ref>Strongly Bound Excitons in Metal-Organic Framework MOF-5: A Many-Body Perturbation Theory Study, A. R. Kshirsagar et al., [https://doi.org/10.26434/chemrxiv.14034917.v1 preprint ChemRxiv]</ref>.		This figure is taken from ref. <ref>Strongly Bound Excitons in Metal-Organic Framework MOF-5: A Many-Body Perturbation Theory Study, A. R. Kshirsagar et al., [https://doi.org/10.26434/chemrxiv.14034917.v1 preprint ChemRxiv]</ref>.

Attacc: /* Plot electron/hole average density (only in Yambo 5.x) */

2021-03-26T08:52:03Z

Plot electron/hole average density (only in Yambo 5.x)

← Older revision		Revision as of 08:52, 26 March 2021
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	ypp -F ypp_WF.in -e w -avehole		ypp -F ypp_WF.in -e w -avehole

	and choose the exciton you want to plot. The electron/hole average densities correspond to generalized valence/conduction orbitals for a given exciton. They are interesting in particular for molecular crystals because they allow distinguishing charge-transfer ~~versus~~ Frenkel ~~excitons~~, ~~from~~ the relative position of the electron/hole densities.		and choose the exciton you want to plot. The electron/hole average densities correspond to generalized valence/conduction orbitals for a given exciton. They are interesting in particular for molecular crystals because they allow to distinguishing charge-transfer exctions from Frenkel or Wannier ones, by looking the relative position of the electron/hole densities.
			For example see the electron/hole average density calculate in a Metal Organic Framework:

	~~If you want see an example of~~ hole~~/electron density of excitons please have a look to~~ ref. <ref>Strongly Bound Excitons in Metal-Organic Framework MOF-5: A Many-Body Perturbation Theory Study, A. R. Kshirsagar et al., [https://doi.org/10.26434/chemrxiv.14034917.v1 preprint ChemRxiv]</ref>.		[[File:Average electron hole.png\|center \| 300px\|Yambo tutorial image]]

			This figure is taken from ref. <ref>Strongly Bound Excitons in Metal-Organic Framework MOF-5: A Many-Body Perturbation Theory Study, A. R. Kshirsagar et al., [https://doi.org/10.26434/chemrxiv.14034917.v1 preprint ChemRxiv]</ref>.

	== Interpolate exciton dispersion (only in Yambo 5.x)==		== Interpolate exciton dispersion (only in Yambo 5.x)==

Fulvio at 16:06, 24 March 2021

2021-03-24T16:06:43Z

← Older revision		Revision as of 16:06, 24 March 2021
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	* analyze a BSE optical spectrum in terms of excitonic eigenvectors and eigenvalues		* analyze a BSE optical spectrum in terms of excitonic eigenvectors and eigenvalues
	* look at the spatial distribution of the exciton		* look at the spatial distribution of the exciton
			* For a similar tutorial focusing on 3D-hBN, go to [[How to analyse excitons - CECAM 2021 school\|this page]].

	== Prerequisites ==		== Prerequisites ==

Attacc: /* Interpolate exciton dispersion (only in Yambo 5.x) */

2021-03-24T13:04:17Z

Interpolate exciton dispersion (only in Yambo 5.x)

← Older revision		Revision as of 13:04, 24 March 2021
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	where iq_start and iq_end is the first and last index of momentum in the irreducible Brillouin zone (IBZ). You can find the list of q-vectors in the r_setup report.		where iq_start and iq_end is the first and last index of momentum in the irreducible Brillouin zone (IBZ). You can find the list of q-vectors in the r_setup report.
	If you calculate the BSE for all q-points of the IBZ, then you can interpolate exciton dispersion along any direction of the full Brillouin zone(BZ) using the		If you calculate the BSE for all q-points of the IBZ, then you can interpolate exciton dispersion along any direction of the full Brillouin zone(BZ) using the
	interpolation scheme of ref. <ref> [https://journals.aps.org/prb/abstract/10.1103/PhysRevB.38.2721 PRB 38 p2721]</ref>, by doing:		interpolation scheme of ref. <ref>Warren E. Pickett, Henry Krakauer, and Philip B. Allen [https://journals.aps.org/prb/abstract/10.1103/PhysRevB.38.2721 PRB 38 p2721 (1988)]</ref>, by doing:

	ypp -e i		ypp -e i

Attacc: /* Interpolate exciton dispersion (only in Yambo 5.x) */

2021-03-24T13:03:08Z

Interpolate exciton dispersion (only in Yambo 5.x)

← Older revision		Revision as of 13:03, 24 March 2021
Line 127:		Line 127:
	where iq_start and iq_end is the first and last index of momentum in the irreducible Brillouin zone (IBZ). You can find the list of q-vectors in the r_setup report.		where iq_start and iq_end is the first and last index of momentum in the irreducible Brillouin zone (IBZ). You can find the list of q-vectors in the r_setup report.
	If you calculate the BSE for all q-points of the IBZ, then you can interpolate exciton dispersion along any direction of the full Brillouin zone(BZ) using the		If you calculate the BSE for all q-points of the IBZ, then you can interpolate exciton dispersion along any direction of the full Brillouin zone(BZ) using the
	interpolation scheme of [https://journals.aps.org/prb/abstract/10.1103/PhysRevB.38.2721 PRB 38 p2721], by doing:		interpolation scheme of ref. <ref> [https://journals.aps.org/prb/abstract/10.1103/PhysRevB.38.2721 PRB 38 p2721]</ref>, by doing:

	ypp -e i		ypp -e i