LIVIVO - Search results -

Search results

Result 1 - 10 of total 577

Search options

Article ; Online: Pulse sequences for manipulating the spin states of molecular radical-pair-based electron spin qubit systems for quantum information applications.

Pazera, Gediminas J / Krzyaniak, Matthew D / Wasielewski, Michael R

2023 Volume 158, Issue 20

Abstract: Molecular qubits are an emerging platform in quantum information science due to the unmatched structural control that chemical design and synthesis provide compared to other leading qubit technologies. This theoretical study investigates pulse sequence ... ...

Abstract	Molecular qubits are an emerging platform in quantum information science due to the unmatched structural control that chemical design and synthesis provide compared to other leading qubit technologies. This theoretical study investigates pulse sequence protocols for spin-correlated radical pairs, which are important molecular spin qubit pair (SQP) candidates. Here, we introduce improved microwave pulse protocols for enhancing the execution times of quantum logic gates based on SQPs. Significantly, this study demonstrates that the proposed pulse sequences effectively remove certain contributions from nuclear spin effects on spin dynamics, which are a common source of decoherence. Additionally, we have analyzed the factors that control the fidelity of the SQP spin state, following the application of the controlled-NOT gate. It was found that higher magnetic fields introduce a high frequency oscillation in the fidelity. Thereupon, it is suggested that further research should be geared toward executing quantum gates at lower magnetic field values. In addition, an absolute bound of the fidelity outcome due to decoherence is determined, which clearly identifies the important factors that control gate execution. Finally, examples of the application of these pulse sequences to SQPs are described.
Language	English
Publishing date	2023-05-31
Publishing country	United States
Document type	Journal Article
ZDB-ID	3113-6
ISSN	1089-7690 ; 0021-9606
ISSN (online)	1089-7690
ISSN	0021-9606
DOI	10.1063/5.0145278
Database	MEDical Literature Analysis and Retrieval System OnLINE

In stock of ZB MED Bonn / Germany

Z 4' 49/16: Show issues

Order via subito

This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Details ▾
- See ZB MED holdings
- Order with fees

Article ; Online: Photogenerated Spin-Correlated Radical Pairs: From Photosynthetic Energy Transduction to Quantum Information Science.

Harvey, Samantha M / Wasielewski, Michael R

Journal of the American Chemical Society

2021 Volume 143, Issue 38, Page(s) 15508–15529

Abstract: More than a half century ago, the NMR spectra of diamagnetic products resulting from radical pair reactions were observed to have strongly enhanced absorptive and emissive resonances. At the same time, photogenerated radical pairs were discovered to ... ...

Abstract	More than a half century ago, the NMR spectra of diamagnetic products resulting from radical pair reactions were observed to have strongly enhanced absorptive and emissive resonances. At the same time, photogenerated radical pairs were discovered to exhibit unusual electron paramagnetic resonance spectra that also had such resonances. These non-Boltzmann, spin-polarized spectra were observed in both chemical systems as well as in photosynthetic reaction center proteins following photodriven charge separation. Subsequent studies of these phenomena led to a variety of chemical electron donor-acceptor model systems that provided a broad understanding of the spin dynamics responsible for these spectra. When the distance between the two radicals is restricted, these observations result from the formation of spin-correlated radical pairs (SCRPs) in which the spin-spin exchange and dipolar interactions between the two unpaired spins play an important role in the spin dynamics. Early on, it was recognized that SCRPs photogenerated by ultrafast electron transfer are entangled spin pairs created in a well-defined spin state. These SCRPs can serve as spin qubit pairs (SQPs), whose spin dynamics can be manipulated to study a wide variety of quantum phenomena intrinsic to the field of quantum information science. This Perspective highlights the role of SCRPs as SQPs, gives examples of possible quantum manipulations using SQPs, and provides some thoughts on future directions.
Language	English
Publishing date	2021-09-17
Publishing country	United States
Document type	Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
ZDB-ID	3155-0
ISSN	1520-5126 ; 0002-7863
ISSN (online)	1520-5126
ISSN	0002-7863
DOI	10.1021/jacs.1c07706
Database	MEDical Literature Analysis and Retrieval System OnLINE

In stock of ZB MED Bonn / Germany

Z 4' 55/32: Show issues
Z 7.3: Show issues

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Details ▾
- See ZB MED holdings
- Order with fees

Article ; Online: Mixed Electronic States in Molecular Dimers: Connecting Singlet Fission, Excimer Formation, and Symmetry-Breaking Charge Transfer.

Young, Ryan M / Wasielewski, Michael R

Accounts of chemical research

2020 Volume 53, Issue 9, Page(s) 1957–1968

Abstract: ConspectusChromophore aggregates are capable of a wide variety of excited-state dynamics that are potentially of great use in optoelectronic devices based on organic molecules. For example, singlet fission, the process by which a singlet exciton is down ... ...

Abstract	ConspectusChromophore aggregates are capable of a wide variety of excited-state dynamics that are potentially of great use in optoelectronic devices based on organic molecules. For example, singlet fission, the process by which a singlet exciton is down converted into two triplet excitons, holds promise for extending the efficiency of solar cells, while other processes, such as excimer formation, are commonly regarded as parasitic pathways or traps. Other processes, such as symmetry-breaking charge transfer, where the excited dimer charge separates into a radical ion pair, can be both a trap and potentially useful in devices, depending on the context. Thus, an understanding of the precise mechanisms of each of these processes is vital to designing tailor-made organic chromophores for molecular optoelectronics.These excited-state phenomena have each been well-studied in recent years and show tantalizing connections as the molecular systems and environments are subtly changed. These seemingly disparate phenomena can be described within the same unifying framework, where each case can be represented as one point in continuum of mixed states. The coherent mixed state is observed experimentally, and it collapses to each of the limiting cases under well-defined conditions. This framework is especially useful in demonstrating the connections between these different states so that we can determine the factors that control their evolution and may ultimately guide the state mixtures to the product state of choice. The emerging picture shows that tuning the electronic coupling through proper arrangement of the chromophores must accompany environmental tuning of the chromophore energies to produce a fully mixed state. Changes in either of these quantities leads to evolution of the admixture and ultimately collapsing the superposition onto a given state, producing one of the photophysical pathways discussed above.In our laboratory, we are utilizing covalent dimers to precisely arrange the chromophores in rigid, well-defined geometries to systematically study the factors that determine the degree of state mixing and its fate. We interrogate these dynamics with transient absorption spectroscopy from the UV continuously into the mid-infrared, along with time-resolved Raman and emission and magnetic resonance spectroscopies to build a complete and detailed molecular level picture of the dynamics of these dimers. The knowledge gained from dimer studies can also be applied to the understanding the dynamics in extended molecular solids. The insight afforded by these studies will help guide the creation of new designer chromophores with control over the fate of the excited state.
Language	English
Publishing date	2020-08-13
Publishing country	United States
Document type	Journal Article
ZDB-ID	1483291-4
ISSN	1520-4898 ; 0001-4842
ISSN (online)	1520-4898
ISSN	0001-4842
DOI	10.1021/acs.accounts.0c00397
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Article: Photogenerated Spin-Correlated Radical Pairs: From Photosynthetic Energy Transduction to Quantum Information Science

Harvey, Samantha M. / Wasielewski, Michael R.

Journal of the American Chemical Society. 2021 Sept. 17, v. 143, no. 38

2021

Abstract	More than a half century ago, the NMR spectra of diamagnetic products resulting from radical pair reactions were observed to have strongly enhanced absorptive and emissive resonances. At the same time, photogenerated radical pairs were discovered to exhibit unusual electron paramagnetic resonance spectra that also had such resonances. These non-Boltzmann, spin-polarized spectra were observed in both chemical systems as well as in photosynthetic reaction center proteins following photodriven charge separation. Subsequent studies of these phenomena led to a variety of chemical electron donor–acceptor model systems that provided a broad understanding of the spin dynamics responsible for these spectra. When the distance between the two radicals is restricted, these observations result from the formation of spin-correlated radical pairs (SCRPs) in which the spin–spin exchange and dipolar interactions between the two unpaired spins play an important role in the spin dynamics. Early on, it was recognized that SCRPs photogenerated by ultrafast electron transfer are entangled spin pairs created in a well-defined spin state. These SCRPs can serve as spin qubit pairs (SQPs), whose spin dynamics can be manipulated to study a wide variety of quantum phenomena intrinsic to the field of quantum information science. This Perspective highlights the role of SCRPs as SQPs, gives examples of possible quantum manipulations using SQPs, and provides some thoughts on future directions.
Keywords	electron paramagnetic resonance spectroscopy ; electron transfer ; energy ; information science ; photosynthetic reaction centers
Language	English
Dates of publication	2021-0917
Size	p. 15508-15529.
Publishing place	American Chemical Society
Document type	Article
ZDB-ID	3155-0
ISSN	1520-5126 ; 0002-7863
ISSN (online)	1520-5126
ISSN	0002-7863
DOI	10.1021/jacs.1c07706
Database	NAL-Catalogue (AGRICOLA)

In stock of ZB MED Bonn / Germany

Z 4' 55/32: Show issues
Z 7.3: Show issues

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Details ▾
- See ZB MED holdings
- Order with fees

Article ; Online: Quantum Gate Operations on a Spectrally Addressable Photogenerated Molecular Electron Spin-Qubit Pair.

Mao, Haochuan / Pažėra, Gediminas J / Young, Ryan M / Krzyaniak, Matthew D / Wasielewski, Michael R

Journal of the American Chemical Society

2023 Volume 145, Issue 11, Page(s) 6585–6593

Abstract: Sub-nanosecond photodriven electron transfer from a molecular donor to an acceptor can be used to generate a radical pair (RP) having two entangled electron spins in a well-defined pure initial singlet quantum state to serve as a spin-qubit pair (SQP). ... ...

Abstract	Sub-nanosecond photodriven electron transfer from a molecular donor to an acceptor can be used to generate a radical pair (RP) having two entangled electron spins in a well-defined pure initial singlet quantum state to serve as a spin-qubit pair (SQP). Achieving good spin-qubit addressability is challenging because many organic radical ions have large hyperfine couplings (HFCs) in addition to significant
Language	English
Publishing date	2023-03-13
Publishing country	United States
Document type	Journal Article
ZDB-ID	3155-0
ISSN	1520-5126 ; 0002-7863
ISSN (online)	1520-5126
ISSN	0002-7863
DOI	10.1021/jacs.3c01243
Database	MEDical Literature Analysis and Retrieval System OnLINE

In stock of ZB MED Bonn / Germany

Z 4' 55/32: Show issues
Z 7.3: Show issues

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Details ▾
- See ZB MED holdings
- Order with fees

Article ; Online: Mechanism of Ultrafast Triplet Exciton Formation in Single Cocrystals of π-Stacked Electron Donors and Acceptors.

Williams, Malik L / Schlesinger, Itai / Jacobberger, Robert M / Wasielewski, Michael R

Journal of the American Chemical Society

2022 Volume 144, Issue 40, Page(s) 18607–18618

Abstract: Ultrafast triplet formation in donor-acceptor (D-A) systems typically occurs by spin-orbit charge-transfer intersystem crossing (SOCT-ISC), which requires a significant orbital angular momentum change and is thus usually observed when the adjacent π ... ...

Abstract	Ultrafast triplet formation in donor-acceptor (D-A) systems typically occurs by spin-orbit charge-transfer intersystem crossing (SOCT-ISC), which requires a significant orbital angular momentum change and is thus usually observed when the adjacent π systems of D and A are orthogonal; however, the results presented here show that subnanosecond triplet formation occurs in a series of D-A cocrystals that form one-dimensional cofacial π stacks. Using ultrafast transient absorption microscopy, photoexcitation of D-A single cocrystals, where D is coronene (Cor) or pyrene (Pyr) and A is
MeSH term(s)	Electron Spin Resonance Spectroscopy ; Electrons ; Naphthalenes ; Perylene/chemistry ; Pyrenes
Chemical Substances	Naphthalenes ; Pyrenes ; Perylene (5QD5427UN7)
Language	English
Publishing date	2022-09-30
Publishing country	United States
Document type	Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
ZDB-ID	3155-0
ISSN	1520-5126 ; 0002-7863
ISSN (online)	1520-5126
ISSN	0002-7863
DOI	10.1021/jacs.2c08584
Database	MEDical Literature Analysis and Retrieval System OnLINE

In stock of ZB MED Bonn / Germany

Z 4' 55/32: Show issues
Z 7.3: Show issues

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Details ▾
- See ZB MED holdings
- Order with fees

Article ; Online: Control of excitation selectivity in pulse EPR on spin-correlated radical pairs with shaped pulses.

Panariti, Daniele / Conron, Sarah M / Zhang, Jinyuan / Wasielewski, Michael R / Di Valentin, Marilena / Tait, Claudia E

Physical chemistry chemical physics : PCCP

2024 Volume 26, Issue 5, Page(s) 3842–3856

Abstract: Spin-correlated radical pairs generated by photoinduced electron transfer are characterised by a distinctive spin polarisation and a unique behaviour in pulse electron paramagnetic resonance (EPR) spectroscopy. Under non-selective excitation, an out-of- ... ...

Abstract	Spin-correlated radical pairs generated by photoinduced electron transfer are characterised by a distinctive spin polarisation and a unique behaviour in pulse electron paramagnetic resonance (EPR) spectroscopy. Under non-selective excitation, an out-of-phase echo signal modulated by the dipolar and exchange coupling interactions characterising the radical pair is observed and allows extraction of geometric information in the two-pulse out-of-phase electron spin echo envelope modulation (ESEEM) experiment. The investigation of the role of spin-correlated radical pairs in a variety of biological processes and in the fundamental mechanisms underlying device function in optoelectronics, as well as their potential use in quantum information science, relies on the ability to precisely address and manipulate the spins using microwave pulses. Here, we explore the use of shaped pulses for controlled narrowband selective and broadband non-selective excitation of spin-correlated radical pairs in two model donor-bridge-acceptor triads, characterised by different spectral widths, at X- and Q-band frequencies. We demonstrate selective excitation with close to rectangular excitation profiles using BURP (band-selective, uniform response, pure-phase) pulses and complete non-selective excitation of both spins of the radical pair using frequency-swept chirp pulses. The use of frequency-swept pulses in out-of-phase ESEEM experiments enables increased modulation depths and, combined with echo transient detection and Fourier transformation, correlation of the dipolar frequencies with the EPR spectrum and therefore the potential to extract additional information on the donor-acceptor pair geometry.
Language	English
Publishing date	2024-01-31
Publishing country	England
Document type	Journal Article
ZDB-ID	1476244-4
ISSN	1463-9084 ; 1463-9076
ISSN (online)	1463-9084
ISSN	1463-9076
DOI	10.1039/d3cp06009h
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Article ; Online: Optical Initialization of Molecular Qubit Spin States Using Weak Exchange Coupling to Photogenerated Fullerene Triplet States.

Mao, Haochuan / Young, Ryan M / Krzyaniak, Matthew D / Wasielewski, Michael R

The journal of physical chemistry. B

2022

Abstract: The ability to initialize an electron spin qubit into a well-defined state is an important criterion for quantum information applications. To achieve this goal, a chromophore photoexcited to its triplet state is used to strongly spin polarize a nearby ... ...

Abstract	The ability to initialize an electron spin qubit into a well-defined state is an important criterion for quantum information applications. To achieve this goal, a chromophore photoexcited to its triplet state is used to strongly spin polarize a nearby stable radical in a series of C
Language	English
Publishing date	2022-12-02
Publishing country	United States
Document type	Journal Article
ISSN	1520-5207
ISSN (online)	1520-5207
DOI	10.1021/acs.jpcb.2c07096
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Ultrafast Charge Transfer Dynamics in a Slip-Stacked Donor-Acceptor-Acceptor System.

Lin, Chenjian / O'Connor, James P / Phelan, Brian T / Young, Ryan M / Wasielewski, Michael R

The journal of physical chemistry. A

2023 Volume 128, Issue 1, Page(s) 244–250

Abstract: Photoexcitation of molecular electron donor and/or acceptor chromophore aggregates can greatly affect their charge-transfer dynamics. Excitonic coupling not only alters the energy landscape in the excited state but may also open new photophysical ... ...

Abstract	Photoexcitation of molecular electron donor and/or acceptor chromophore aggregates can greatly affect their charge-transfer dynamics. Excitonic coupling not only alters the energy landscape in the excited state but may also open new photophysical pathways, such as symmetry-breaking charge separation (SB-CS). Here, we investigate the impact of excitonic coupling on a covalent donor-acceptor-acceptor system comprising a perylene donor (Per) and two perylenediimide (PDI) acceptor chromophores in which the three components are π-stacked in a geometry that is slipped along their long axes (
Language	English
Publishing date	2023-12-28
Publishing country	United States
Document type	Journal Article
ISSN	1520-5215
ISSN (online)	1520-5215
DOI	10.1021/acs.jpca.3c07539
Database	MEDical Literature Analysis and Retrieval System OnLINE

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Article ; Online: Ligand Desorption and Fragmentation in Oleate-Capped CdSe Nanocrystals under High-Intensity Photoexcitation.

Harvey, Samantha M / Olshansky, Jacob H / Li, Alice / Panuganti, Shobhana / Kanatzidis, Mercouri G / Hupp, Joseph T / Wasielewski, Michael R / Schaller, Richard D

Journal of the American Chemical Society

2024 Volume 146, Issue 6, Page(s) 3732–3741

Abstract: Semiconductor nanocrystals (NCs) offer prospective use as active optical elements in photovoltaics, light-emitting diodes, lasers, and photocatalysts due to their tunable optical absorption and emission properties, high stability, and scalable solution ... ...

Abstract	Semiconductor nanocrystals (NCs) offer prospective use as active optical elements in photovoltaics, light-emitting diodes, lasers, and photocatalysts due to their tunable optical absorption and emission properties, high stability, and scalable solution processing, as well as compatibility with additive manufacturing routes. Over the course of experiments, during device fabrication, or while in use commercially, these materials are often subjected to intense or prolonged electronic excitation and high carrier densities. The influence of such conditions on ligand integrity and binding remains underexplored. Here, we expose CdSe NCs to laser excitation and monitor changes in oleate that is covalently attached to the NC surface using nuclear magnetic resonance as a function of time and laser intensity. Higher photon doses cause increased rates of ligand loss from the particles, with upward of 50% total ligand desorption measured for the longest, most intense excitation. Surprisingly, for a range of excitation intensities, fragmentation of the oleate is detected and occurs concomitantly with formation of aldehydes, terminal alkenes, H
Language	English
Publishing date	2024-02-01
Publishing country	United States
Document type	Journal Article
ZDB-ID	3155-0
ISSN	1520-5126 ; 0002-7863
ISSN (online)	1520-5126
ISSN	0002-7863
DOI	10.1021/jacs.3c10232
Database	MEDical Literature Analysis and Retrieval System OnLINE

In stock of ZB MED Bonn / Germany

Z 4' 55/32: Show issues
Z 7.3: Show issues

Order via subito

Inter-library loan at ZB MED

Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

Details ▾
- See ZB MED holdings
- Order with fees

To top

More links

Kategorien

In stock of ZB MED Bonn / Germany

Order via subito

Inter-library loan at ZB MED

More links

Kategorien

In stock of ZB MED Bonn / Germany

Order via subito

Inter-library loan at ZB MED

More links

Kategorien

Order via subito

More links

Kategorien

In stock of ZB MED Bonn / Germany

Order via subito

Inter-library loan at ZB MED

More links

Kategorien

In stock of ZB MED Bonn / Germany

Order via subito

Inter-library loan at ZB MED

More links

Kategorien

In stock of ZB MED Bonn / Germany

Order via subito

Inter-library loan at ZB MED

More links

Kategorien

Order via subito

More links

Kategorien

Order via subito

Inter-library loan at ZB MED

More links

Kategorien

Order via subito

Inter-library loan at ZB MED

More links

Kategorien

In stock of ZB MED Bonn / Germany

Order via subito

Inter-library loan at ZB MED