Renormalized excitonic method in terms of block excitations: Application to spin lattices

Hajj, Mohamad Al; Malrieu, Jean‐Paul; Guihéry, Nathalie

doi:10.1103/physrevb.72.224412

Cited by 29 publications

(29 citation statements)

References 25 publications

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“…Although some approximate approaches, including constrained density functional theory (CDFT) and classical micro‐electrostatic (ME) techniques, were successfully applied for the energetic calculations for the D/A heterojunctions in recent years, such methods cannot be used to evaluate the absorption intensities of various CT states due to their neglect of the couplings between different CT configurations and the consequent charge delocalization. To include such coupling terms in the electronic structure calculations, here we adopted our newly developed renormalized exciton method (REM), which is based on the assumption that the low‐lying delocalized electronic state can be approximately described by a linear combination of many local excitations or ionizations through effective couplings between them and which is capable of calculating various delocalized electronic states including excitations and ionizations and incorporating correctly the screening effect with high accuracy for large molecular aggregates. Here REM calculations were implemented at the TDDFT level with the long‐range‐corrected exchange‐correlation functional CAM‐B3LYP and the 6–31G(d) Pople polarized valence double‐zeta basis set.…”

Section: Acknowledgementsmentioning

confidence: 99%

Direct Optical Generation of Long‐Range Charge‐Transfer States in Organic Photovoltaics

Troisi

2014

Advanced Materials

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Direct optical excitation of long-range charge-transfer (CT) states in organic photovoltaics is shown to be feasible, a fact that is ascribed to the very low but non-vanishing oscillator strength of each individual transition and the much higher density of states (DOS) as compared with their short-range counterparts. This finding provides a new framework to interpret the low-energy absorption spectra of photovoltaic devices and to correlate this property with the optoelectronic conversion process in working devices.

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Section: Acknowledgementsmentioning

confidence: 99%

Direct Optical Generation of Long‐Range Charge‐Transfer States in Organic Photovoltaics

Troisi

2014

Advanced Materials

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“…We are currently working in this direction, particularly in coordination with fragmentation approaches in quantum chemistry, such as molecular fractionation with conjugate caps 110 − 112 and the renormalized exciton method. 113 − 115 …”

Section: Discussionmentioning

confidence: 99%

Forecasting System of Computational Time of DFT/TDDFT Calculations under the Multiverse Ansatz via Machine Learning and Cheminformatics

Zhang

et al. 2021

ACS Omega

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With the view of achieving a better performance in task assignment and load-balancing, a top-level designed forecasting system for predicting computational times of density-functional theory (DFT)/time-dependent DFT (TDDFT) calculations is presented. The computational time is assumed as the intrinsic property for the molecule. Based on this assumption, the forecasting system is established using the “reinforced concrete”, which combines the cheminformatics, several machine-learning (ML) models, and the framework of many-world interpretation (MWI) in multiverse ansatz. Herein, the cheminformatics is used to recognize the topological structure of molecules, the ML models are used to build the relationships between topology and computational cost, and the MWI framework is used to hold various combinations of DFT functionals and basis sets in DFT/TDDFT calculations. Calculated results of molecules from the DrugBank dataset show that (1) it can give quantitative predictions of computational costs, typical mean relative errors can be less than 0.2 for DFT/TDDFT calculations with derivations of ±25% using the exactly pretrained ML models and (2) it can also be employed to various combinations of DFT functional and basis set cases without exactly pretrained ML models, while only slightly enlarge predicting errors.

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“…The excitonic matrix is isomorphic to a Hü ckel one, the lowest root of which is well known. We may obtain an analytic expression of the lowest excitation energy DE *1 , as far as all the h IJ terms are negative: [29] …”

Section: Renormalized Excitonic Methods At Ab Initio Levelmentioning

confidence: 99%

“…The excitonic method [29] takes benefit of the fact that the lowest ionization process essentially concerns the highest valence MOs, which may be built from the highest occupied va- …”

Section: Renormalized Excitonic Methods At Ab Initio Levelmentioning

confidence: 99%

“…This is what will be done here. One of us (Jean-Paul Malrieu) proposed renormalized excitonic method (REM), [29] taking advantage of the scale change concept, as performed in real space renormalized group (RSRG) [30] and in the recent contractor renormalization (CORE) method [31][32][33][34][35] and RSRG-EI (RSRG with effective interactions). [36][37][38] The scale change allows one to go from the electrons and monoelectronic functions to a limited number of polyelectronic functions relative to blocks of atoms.…”

Section: Original Articlesmentioning

confidence: 99%

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Implementation of renormalized excitonic method at ab initio level

Zhang

Malrieu

et al. 2011

J Comput Chem

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The renormalized excitonic method [Hajj et al., Phys Rev B 2005, 72, 224412], in which the excited state of the whole system may be described as a linear combination of local excitations, has been implemented at ab initio level. Its performance is tested on the ionization potential and the energy gap between singlet ground state and lowest triplet for linear molecular hydrogen chains and more realistic systems, such as polyenes and polysilenes, using full configuration interaction (FCI) wave functions with a minimal basis set. The influence of different block sizes and the extent of interblock interactions are investigated. It has been demonstrated that satisfactory results can be obtained if the near degeneracies between the model space and the outer space are avoided and if interactions between the next-nearest neighbor blocks are considered. The method can be used with larger basis sets and other accurate enough ab initio evaluations (instead of FCI) of local excited states, from blocks, or from dimers or trimers of blocks. It provides a new possibility to accurately and economically describe the low-lying delocalized excited states of large systems, even inhomogeneous ones.

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Renormalized excitonic method in terms of block excitations: Application to spin lattices

Cited by 29 publications

References 25 publications

Direct Optical Generation of Long‐Range Charge‐Transfer States in Organic Photovoltaics

Direct Optical Generation of Long‐Range Charge‐Transfer States in Organic Photovoltaics

Forecasting System of Computational Time of DFT/TDDFT Calculations under the Multiverse Ansatz via Machine Learning and Cheminformatics

Implementation of renormalized excitonic method at ab initio level

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