A novel non-adiabatic spin relaxation mechanism in molecular qubits

The Journal of Chemical Physics, Год журнала: 2024, Номер 160(16)

Опубликована: Апрель 23, 2024

The interaction of electronic spin and molecular vibrations mediated by spin-orbit coupling governs relaxation in qubits. We derive an extended Hamiltonian that includes both adiabatic non-adiabatic spin-dependent interactions, we implement the computation its matrix elements using state-of-the-art density functional theory. new contains a novel spin-vibrational orbit with origin, together traditional Zeeman zero-field splitting interactions origin. represents non-Abelian Berry curvature on ground-state manifold corresponds to effective magnetic field dynamics. further develop rate model estimates time via two-phonon Raman process. An application Cu(II) porphyrin, prototypical S = 1/2 qubit, demonstrates at elevated temperatures is dominated interaction. computed orientation dependence are excellent agreement experimental measurements.

Язык: Английский

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Towards understanding and controlling ultrafast dynamics in molecular photomagnets

Coordination Chemistry Reviews, Год журнала: 2023, Номер 494, С. 215346 - 215346

Опубликована: Июль 27, 2023

Manipulating magnetic materials is the cornerstone of hard drive technology. This modern information technology era has led to an explosive increase in rate data generation and storage creating urgent need achieve a new faster more efficient devices. The development ultrafast femtosecond lasers created possibility control properties using ultrashort pulses light therefore study magnetisation dynamics become one most active fields magnetism driven by both fundamental technological interest. However, major challenge this field understanding microscopic mechanisms responsible. Indeed, excited state initiated upon interaction with laser are characterised strong coupling between electronic, vibrational spin degrees freedom. especially pertinent for case single-molecule magnets, which focus review, due high density electronically states dense manifold within energy range In contribution, we discuss recent experimental theoretical developments seeking understand associated molecular photomagnets explore opportunities they offer as well outlining some future required field.

Язык: Английский

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Intramolecular bridging strategies to suppress two-phonon Raman spin relaxation in dysprosocenium single-molecule magnets

Physical Chemistry Chemical Physics, Год журнала: 2024, Номер 26(25), С. 17539 - 17548

Опубликована: Янв. 1, 2024

Dy(III) bis-cyclopentadienyl (Cp) sandwich compounds exhibit extremely strong single-ion magnetic anisotropy which imbues them with memory effects such as hysteresis, and has put at the forefront of high-performance single-molecule magnets (SMMs). Owing to great success design principles focused on maximising barrier, ever higher

Язык: Английский

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Dynamic Magnetic Susceptibility Method in Studies of Coordination Compounds

Russian Journal of Coordination Chemistry, Год журнала: 2024, Номер 50(6), С. 363 - 373

Опубликована: Июнь 1, 2024

Abstract The measurement of the dynamic magnetic susceptibility is a universal method, which used for evaluation properties single molecule magnets by scientists all over world. An information in Russian scientific literature that can be useful practical mastering this method presently insufficient. To fill gap, work we present detailed procedure magnetochemical experiment observing slow relaxation coordination compounds 3 d - and 4 f -element ions complete characterization dynamics behavior. Special attention given to usually omitted but important details related stages studying dynamics. main variants sample preparation are described, logics construction measuring sequence experimental data processing discussed, advantages drawbacks some programs calculation considered. concepts equations analysis presented, primary conclusions made from obtained results proposed.

Язык: Английский

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Approximate Hamiltonians from a Linear Vibronic Coupling Model for Solution-Phase Spin Dynamics

Journal of Chemical Theory and Computation, Год журнала: 2025, Номер unknown

Опубликована: Янв. 17, 2025

The linear vibronic coupling (LVC) model is an approach for approximating how a molecular Hamiltonian changes in response to small geometry. LVC framework thus has the ability approximate Hamiltonians at low computational expense but with quality approaching multiconfigurational ab initio calculations, when change geometry compared reference calculation used parametrize it small. Here, we show can be project spin of solvated lanthanide complex along room-temperature dynamics trajectory. As expected, approximation less accurate as diverges from that which was parametrized. We examine accuracy predicted by performing time-dependent quantum simulations molecule, obtained using projected calculations each step. find quantitatively behavior parametrizations are performed least every 10 fs during

Язык: Английский

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In-Field and Zero-Field Relaxation Dynamics of Dysprosocenium in Solution

The Journal of Physical Chemistry A, Год журнала: 2025, Номер 129(9), С. 2144 - 2150

Опубликована: Фев. 25, 2025

Most of the work in expanding frontiers single-molecule magnets employs chemical design new molecules to increase size effective barrier (Ueff) or hysteresis temperature (TH). Here we explore how perturbing local environment affects magnetic relaxation properties by dissolving [Dy(Cpttt)2][B(C6F5)4] two different solvents: difluorobenzene (DFB) and dichloromethane (DCM). Surprisingly, find no significant effects phonon-driven Raman-I regime at higher temperatures, but do observe that frozen-solution increases rate quantum tunneling magnetization (QTM) due an avoided level crossing. We there is a drastic decrease Raman low temperatures for concentrated DCM polycrystalline samples under applied field where QTM process quenched, which attributed changes low-energy phonon spectrum not replicated other samples.

Язык: Английский

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Paramagnetic relaxation: Direct and Raman relaxation of spin S=12

Journal of Magnetic Resonance Open, Год журнала: 2025, Номер unknown, С. 100193 - 100193

Опубликована: Март 1, 2025

Язык: Английский

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Role of Electron Correlation beyond the Active Space in Achieving Quantitative Predictions of Spin-Phonon Relaxation

Journal of Chemical Theory and Computation, Год журнала: 2025, Номер unknown

Опубликована: Март 12, 2025

Single-molecule magnets (SMMs) are promising candidates for molecular-scale data storage and processing due to their strong magnetic anisotropy long spin relaxation times. However, as the temperature rises, interactions between electronic states lattice vibrations accelerate relaxation, significantly limiting practical applications. Recently, ab initio simulations have made it possible advance our understanding of phonon-induced but significant deviations from experiments often been observed. The description molecules' structure has mostly based on complete active space self-consistent field (CASSCF) calculations, impact electron correlation beyond remains largely unexplored. In this study, we provide first systematic investigation spin-phonon in SMMs with post-CASSCF multiconfigurational methods, specifically CAS, followed by second-order perturbation theory multiconfiguration pair-density functional theory. Taking Co(II)- Dy(III)-based case studies, analyze how influences rates across a range temperatures comparing theoretical predictions experimental observations. Our findings demonstrate that treatments make achieve quantitative Co(II)-based SMMs. For systems, however, accurate require consideration additional effects, underscoring urgent necessity further advancing study effects these complex systems.

Язык: Английский

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Chiral Pseudo-D6h Dy(III) Single-Molecule Magnet Based on a Hexaaza Macrocycle

Molecules, Год журнала: 2025, Номер 30(9), С. 2043 - 2043

Опубликована: Май 3, 2025

A mononuclear complex [Dy(phenN6)(HL′)2]PF6·CH2Cl2 (H2L′ = R/S-1,1′-binaphthyl-2,2′-diphenol) with local D6h symmetry was synthesized. Structural determination shows that Dy3+ encapsulated within the coordination cavity of neutral hexaaza macrocyclic ligand phenN6, forming a non-planar environment. The axial positions are occupied by two phenoxy groups binaphthol in trans form. geometry closely resembles regular hexagonal bipyramid configuration. Dy-Ophenoxy distances 2.189(5) and 2.145(5) Å, respectively, while Dy-N bond lengths equatorial plane range 2.524(7)–2.717(5) Å. Ophthalmoxy-Dy-Ophthalmoxy angle is 162.91(17)°, which deviates from ideal linearity. Under excitation at 320 nm, exhibits characteristic emission peak 360 corresponding to naphthalene ring. AC susceptibility measurements under an applied DC field 1800 Oe show distinct temperature-dependent frequency-dependent magnetic susceptibility, typical single-molecule behavior. Cole–Cole plot temperature 6.0–28.0 K fitted using model incorporating Orbach Raman relaxation mechanisms, giving effective energy barrier Ueff 300.2 K. Theoretical calculations on 1 reveal magnetization proceeds through first excited Kramers doublets calculated blocking 404.1 cm−1 (581.4 K).

Язык: Английский

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Homoleptic Rare-Earth-Metal Sandwiches with Dibenzo[a,e]cyclooctatetraene Dianions

Inorganic Chemistry, Год журнала: 2024, Номер 63(21), С. 9579 - 9587

Опубликована: Фев. 20, 2024

A family of rare-earth complexes [RE(III) = Y, La, Gd, Tb, Dy, and Er] with doubly reduced dibenzo[a,e]cyclooctatetraene (DBCOT) has been synthesized structurally characterized. X-ray diffraction analysis confirms that all products the [RE(DBCOT)(THF)4][RE(DBCOT)2] composition consist anionic sandwich [RE(DBCOT)2]− cationic counterpart [RE(DBCOT)(THF)4]+. Within sandwich, two elongated π decks are slightly bent toward metal center (avg. 7.3°) a rotation angle 35.9–37.6°. The RE(III) ion is entrapped between central eight-membered rings DBCOT2– in η8 fashion. trends RE–COT bond lengths consistent variations ionic radii centers. 1H NMR spectra diamagnetic Y(III) La(III) analogues illustrate distinct solution behavior for parts this series. Magnetic measurements Dy analogue reveal single-molecule magnetism, which was rationalized by considering effect crystal-field splitting both building units analyzed electronic structure calculations.

Язык: Английский

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