scholarly journals Quantum annealing using vacuum states as effective excited states of driven systems

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Hayato Goto ◽  
Taro Kanao
Keyword(s):  
Excited State ◽  
Excited States ◽  
Energy Gap ◽  
Stable State ◽  
Vacuum State ◽  
Quantum Systems ◽  
Quantum Annealing ◽  
Nonadiabatic Transition ◽  
Vacuum States ◽  
Gap Closing

AbstractQuantum annealing, which is particularly useful for combinatorial optimization, becomes more powerful by using excited states, in addition to ground states. However, such excited-state quantum annealing is prone to errors due to dissipation. Here we propose excited-state quantum annealing started with the most stable state, i.e., vacuum states. This counterintuitive approach becomes possible by using effective energy eigenstates of driven quantum systems. To demonstrate this concept, we use a network of Kerr-nonlinear parametric oscillators, where we can start excited-state quantum annealing with the vacuum state of the network by appropriately setting initial detuning frequencies for the oscillators. By numerical simulations of four oscillators, we show that the present approach can solve some hard instances whose optimal solutions cannot be obtained by standard ground-state quantum annealing because of energy-gap closing. In this approach, a nonadiabatic transition at an energy-gap closing point is rather utilized. We also show that this approach is robust against errors due to dissipation, as expected, compared to quantum annealing started with physical excited (i.e., nonvacuum) states. These results open new possibilities for quantum computation and driven quantum systems.

Photoinduced ligand dissociation follows reverse energy gap law: nitrile photodissociation from low energy 3MLCT excited states

2020 ◽  
Vol 56 (29) ◽  
pp. 4070-4073
Author(s):  
Lauren M. Loftus ◽  
Jeffrey J. Rack ◽  
Claudia Turro
Keyword(s):  
Excited State ◽  
Excited States ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Energy Gap ◽  
Low Energy ◽  
Transient Absorption Spectroscopy ◽  
Ligand Dissociation ◽  
Energy Gap Law

Transient absorption spectroscopy is used to show that stabilization of the 3MLCT excited state in a series of Ru(ii) complexes leads to decreased population of the 3LF state, but does not reduce the efficiency of photoinduced nitrile dissociation.

scholarly journals Direct estimation of the energy gap between the ground state and excited state with quantum annealing

2021 ◽  
Vol 60 (SB) ◽  
pp. SBBI02
Author(s):  
Yuichiro Matsuzaki ◽  
Hideaki Hakoshima ◽  
Kenji Sugisaki ◽  
Yuya Seki ◽  
Shiro Kawabata
Keyword(s):  
Excited State ◽  
Ground State ◽  
Energy Gap ◽  
Quantum Annealing ◽  
Direct Estimation

scholarly journals Computational investigation on the large energy gap between the triplet excited-states in acenes

RSC Advances ◽  
2017 ◽  
Vol 7 (43) ◽  
pp. 26697-26703 ◽  
Author(s):  
Y. Y. Pan ◽  
J. Huang ◽  
Z. M. Wang ◽  
D. W. Yu ◽  
B. Yang ◽  
...  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Organic Materials ◽  
Energy Gap ◽  
Great Influence ◽  
Accurate Description ◽  
Large Energy ◽  
Computational Investigation ◽  
State Behavior ◽  
Triplet Excited States

Accurate description triplet excited states is a challenge of organic materials. In this work, we investigate excited state behavior of acenes. The results show that the symmetry of the transition orbital have a great influence on the energy gap.

scholarly journals Tuning the singlet-triplet energy gap: a unique approach to efficient photosensitizers with aggregation-induced emission (AIE) characteristics

2015 ◽  
Vol 6 (10) ◽  
pp. 5824-5830 ◽  
Author(s):  
Shidang Xu ◽  
Youyong Yuan ◽  
Xiaolei Cai ◽  
Chong-Jing Zhang ◽  
Fang Hu ◽  
...  
Keyword(s):  
Excited State ◽  
Excited States ◽  
Energy Gap ◽  
Intersystem Crossing ◽  
Triplet Excited State ◽  
Triplet Energy ◽  
Aggregation Induced Emission ◽  
Unique Approach ◽  
Triplet Excited States

The efficiency of the intersystem crossing process can be improved by reducing the energy gap between the singlet and triplet excited states (ΔEST), which offers the opportunity to improve the yield of the triplet excited state.

scholarly journals Influence of energy gap between charge-transfer and locally excited states on organic long persistence luminescence

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Zesen Lin ◽  
Ryota Kabe ◽  
Kai Wang ◽  
Chihaya Adachi
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Energy Gap ◽  
Persistent Luminescence ◽  
Triplet Excited State ◽  
Exciton Energy ◽  
Selection Strategies ◽  
Molecular Selection ◽  
Spectra Properties

AbstractOrganic long-persistent luminescence (LPL) is an organic luminescence system that slowly releases stored exciton energy as light. Organic LPL materials have several advantages over inorganic LPL materials in terms of functionality, flexibility, transparency, and solution-processability. However, the molecular selection strategies for the organic LPL system still remain unclear. Here we report that the energy gap between the lowest localized triplet excited state and the lowest singlet charge-transfer excited state in the exciplex system significantly controls the LPL performance. Changes in the LPL duration and spectra properties are systematically investigated for three donor materials having a different energy gap. When the energy level of the lowest localized triplet excited state is much lower than that of the charge-transfer excited state, the system exhibits a short LPL duration and clear two distinct emission features originating from exciplex fluorescence and donor phosphorescence.

Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Transient Absorption ◽  
Electronic Energy ◽  
Transient Absorption Spectroscopy ◽  
Electronic Relaxation ◽  
Vibrationally Excited ◽  
Excited State Dynamics ◽  
Π State

<p></p><p> Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived <sup>1</sup>n<sub>O</sub>π* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived <sup>3</sup>ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.</p><p></p>

The Malleable Excited States of Benzothiadiazole Dyes and Investigation of their Potential for Photochemical Control

2019 ◽  
Author(s):  
Caroline C. Warner ◽  
andrea thooft ◽  
Bryan J. Lampkin ◽  
selin demirci ◽  
Brett VanVeller
Keyword(s):  
Excited State ◽  
Excited States ◽  
Polar Solvent ◽  
Nonpolar Solvent ◽  
Photochemical Degradation ◽  
Solvent Lead ◽  
Environmentally Sensitive

<p>A strategy to control the efficiency of a photocleavage reaction based on changing the nature of the excited state is presented. A novel class of photoactive compounds has been synthesized by combining the classical o-nitrobenzyl scaffold with an environmentally sensitive dye, 4-amino-nitrobenzothiazole. Irradiation in a polar solvent lead to an excited state that is inoperative for photochemistry whereas excitation in a nonpolar solvent lead to an excited state that is photochemically active. A photochemical degradation appears to be the preferred process in contrast to the intended photocleavage process.</p>

Excited State Tracking During the Relaxation of Coordination Compounds

2018 ◽  
Author(s):  
Juan Sanz García ◽  
Martial Boggio-Pasqua ◽  
Ilaria Ciofini ◽  
Marco Campetella
Keyword(s):  
Excited State ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Photochemical Reactions ◽  
Complex Nature ◽  
Electronic Excited States ◽  
Ruthenium Nitrosyl ◽  
State Tracking ◽  
Energy Surfaces ◽  
Electronic Wavefunction

<div>The ability to locate minima on electronic excited states (ESs) potential energy surfaces (PESs) both in the case of bright and dark states is crucial for a full understanding of photochemical reactions. This task has become a standard practice for small- to medium-sized organic chromophores thanks to the constant developments in the field of computational photochemistry. However, this remains a very challenging effort when it comes to the optimization of ESs of transition metal complexes (TMCs), not only due to the presence of several electronic excited states close in energy, but also due to the complex nature of the excited states involved. In this article, we present a simple yet powerful method to follow an excited state of interest during a structural optimization in the case of TMC, based on the use of a compact hole-particle representation of the electronic transition, namely the natural transition orbitals (NTOs). State tracking using NTOs is unambiguously accomplished by computing the mono-electronic wavefunction overlap between consecutive steps of the optimization. Here, we demonstrate that this simple but robust procedure works not only in the case of the cytosine but also in the case of the ES optimization of a ruthenium-nitrosyl complex which is very problematic with standard approaches.</div>

scholarly journals Ground- and excited-state characteristics in photovoltaic polymer N2200

RSC Advances ◽  
2021 ◽  
Author(s):  
Guanzhao Wen ◽  
Xianshao Zou ◽  
Rong Hu ◽  
Jun Peng ◽  
Zhifeng Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Steady State ◽  
Excited States ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Time Dependent ◽  
Functional Theory ◽  
Time Resolved ◽  
Dependent Density

Ground- and excited-states properties of N2200 have been studied by steady-state and time-resolved spectroscopies as well as time-dependent density functional theory calculations.

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