scholarly journals A New Benchmark Set for Excitation Energy of Charge Transfer States: Systematic Investigation of Coupled Cluster Type Methods

2020 ◽  
Vol 16 (7) ◽  
pp. 4213-4225 ◽  
Author(s):  
Balázs Kozma ◽  
Attila Tajti ◽  
Baptiste Demoulin ◽  
Róbert Izsák ◽  
Marcel Nooijen ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excitation Energy ◽  
Systematic Investigation ◽  
Coupled Cluster ◽  
Cluster Type

scholarly journals A New Benchmark Set for Excitation Energy of Charge Transfer States: Systematic Investigation of Coupled-Cluster Type Methods

2020 ◽  
Author(s):  
Balázs Kozma ◽  
Attila Tajti ◽  
Baptiste Demoulin ◽  
Róbert Izsák ◽  
Marcel Nooijen ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excitation Energy ◽  
Systematic Investigation ◽  
Coupled Cluster ◽  
Excitation Energies ◽  
Chemical Methods ◽  
Valence States ◽  
Quantum Chemical Methods ◽  
Material Physics ◽  
Cluster Methods

There are numerous publications on benchmarking quantum chemistry methods for excited states. These studies rarely include Charge Transfer (CT) states although many interesting phenomena in e.g. biochemistry and material physics involve transfer of electron between fragments of the system. Therefore, it is timely to test the accuracy of quantum chemical methods for CT states, as well. In this study we first suggest a set benchmark systems consisting of dimers having low-energy CT states. On this set, the excitation energy has been calculated with coupled cluster methods including triple excitations (CC3, CCSDT-3, CCSD(T)(a)* ), as well as with methods including full or approximate doubles (CCSD, STEOM-CCSD, CC2, ADC(2), EOM-CCSD(2)). The results show that the popular CC2 and ADC(2) methods are much more inaccurate for CT states than for valence states. On the other hand, CCSD seems to have similar systematic overestimation of the excitation energies for both valence and CT states. Concerning triples methods, the new CCSD(T)(a)* method including non-iterative triple excitations preforms very well for all type of states, delivering essentially CCSDT quality results.<br>

scholarly journals A New Benchmark Set for Excitation Energy of Charge Transfer States: Systematic Investigation of Coupled-Cluster Type Methods

2020 ◽  
Author(s):  
Balázs Kozma ◽  
Attila Tajti ◽  
Baptiste Demoulin ◽  
Róbert Izsák ◽  
Marcel Nooijen ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excitation Energy ◽  
Systematic Investigation ◽  
Coupled Cluster ◽  
Excitation Energies ◽  
Chemical Methods ◽  
Valence States ◽  
Quantum Chemical Methods ◽  
Material Physics ◽  
Cluster Methods

There are numerous publications on benchmarking quantum chemistry methods for excited states. These studies rarely include Charge Transfer (CT) states although many interesting phenomena in e.g. biochemistry and material physics involve transfer of electron between fragments of the system. Therefore, it is timely to test the accuracy of quantum chemical methods for CT states, as well. In this study we first suggest a set benchmark systems consisting of dimers having low-energy CT states. On this set, the excitation energy has been calculated with coupled cluster methods including triple excitations (CC3, CCSDT-3, CCSD(T)(a)* ), as well as with methods including full or approximate doubles (CCSD, STEOM-CCSD, CC2, ADC(2), EOM-CCSD(2)). The results show that the popular CC2 and ADC(2) methods are much more inaccurate for CT states than for valence states. On the other hand, CCSD seems to have similar systematic overestimation of the excitation energies for both valence and CT states. Concerning triples methods, the new CCSD(T)(a)* method including non-iterative triple excitations preforms very well for all type of states, delivering essentially CCSDT quality results.<br>

Coupled-pair theories and Davidson-type corrections for quasidegenerate states: The H4 model revisited

1988 ◽  
Vol 53 (9) ◽  
pp. 1919-1942 ◽  
Author(s):  
Josef Paldus ◽  
Paul E. S. Wormer ◽  
Marc Benard
Keyword(s):  
Electron Correlation ◽  
Model System ◽  
Coupled Cluster ◽  
Electron Model ◽  
Hydrogen Molecules ◽  
Double Zeta ◽  
Correlation Problem ◽  
Variational Approaches ◽  
Cluster Type ◽  
The Many

The performance of various variational and non-variational approaches to the many-electron correlation problem is examined for a simple four-electron model system consisting of two stretched hydrogen molecules in trapezoidal, rectangular and linear configurations, in which the degree of quasi-degeneracy can be continuously varied from a non-degenerate to an almost degenerate situation. In contrast to an earlier work (K. Jankowski and J. Paldus, Int. J. Quantum Chem. 18, 1243 (1980)) we employ a double-zeta plus polarization basis and examine both single reference and multireference configuration interaction and coupled-cluster-type approaches. The performance of various Davidson-type corrections is also investigated.

scholarly journals A feasible approach for automatically differentiable unitary coupled-cluster on quantum computers

2021 ◽  
Author(s):  
Jakob S. Kottmann ◽  
Abhinav Anand ◽  
Alán Aspuru-Guzik
Keyword(s):  
Coupled Cluster ◽  
Quantum Computers ◽  
Evaluation Procedures ◽  
Cluster Type

We develop computationally affordable and encoding independent gradient evaluation procedures for unitary coupled-cluster type operators, applicable on quantum computers.

scholarly journals THE EXCITATION ENERGY AND CHARGE TRANSFER IN DONOR-ACCEPTOR SYSTEMS BASED ON SEMICONDUCTOR POLYMER

2018 ◽  
Vol 218 (6) ◽  
pp. 110-115
Author(s):  
E.K. Alidzhanov ◽  
◽  
Yu.D. Lantukh ◽  
S.N. Letuta ◽  
S.N. Pashkevitch ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Excitation Energy ◽  
Donor Acceptor

scholarly journals Ultrafast charge transfer dynamics in 2D Covalent Organic Frameworks/Re-complex hybrid photocatalyst for CO2 reduction: hot electrons vs. cold electrons

2021 ◽  
Author(s):  
Qinying Pan ◽  
Mohamed Abdellah ◽  
Yuehan Cao ◽  
Yang Liu ◽  
Weihua Lin ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excitation Energy ◽  
Co2 Reduction ◽  
Underlying Mechanism ◽  
High Energy ◽  
Hot Electrons ◽  
Covalent Organic Frameworks ◽  
Energy Excitation ◽  
Energy Dependent

Abstract Rhenium(I)-carbonyl-diimine complexes are promising photocatalysts for CO2 reduction. Covalent organic frameworks (COFs) can be perfect sensitizers to enhance the reduction activities. Here we investigated the excited state dynamics of COF (TpBpy) with 2,2'-bipyridine incorporating Re(CO)5Cl (Re-TpBpy) to rationalize the underlying mechanism. The time-dependent DFT calculation first clarified excited state structure of the hybrid catalyst. The studies from transient visible and infrared spectroscopies revealed the excitation energy-dependent photo-induced charge transfer pathways in Re-TpBpy. Under low energy excitation, the electrons at the LUMO level are quickly injected from Bpy into ReI center (1–2 ps) followed by backward recombination (13 ps). Under high energy excitation, the hot-electrons are first injected into the higher unoccupied level of ReI center (1–2 ps) and then slowly relax back to the HOMO in COF (24 ps). There also remains long-lived free electrons in the COF moiety. This explained the excitation energy-dependent CO2 reduction performance in our system.

Ultrafast excited state dynamics of fucoxanthin: excitation energy dependent intramolecular charge transfer dynamics

2011 ◽  
Vol 13 (22) ◽  
pp. 10762 ◽  
Author(s):  
Daisuke Kosumi ◽  
Toshiyuki Kusumoto ◽  
Ritsuko Fujii ◽  
Mitsuru Sugisaki ◽  
Yoshiro Iinuma ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excitation Energy ◽  
Intramolecular Charge Transfer ◽  
Excited State Dynamics ◽  
Charge Transfer Dynamics ◽  
Energy Dependent
Sign in / Sign up

Export Citation Format

Share Document