³¹P NMR Chemical Shift Anisotropy in Paramagnetic Lanthanide Phosphide Complexes

JACS Au, Journal Year: 2025, Volume and Issue: 5(3), P. 1196 - 1212

Published: Feb. 21, 2025

Lanthanide (Ln) magnetic resonance imaging and chiral shift reagents generally exploit 1H NMR shifts, as paramagnetic broadening tends to preclude the use of heavier, less sensitive nuclei. Here, we report solution solid-state 31P shifts an isostructural series distorted trigonal bipyramidal Ln(III) tris-silylphosphide complexes, [Ln{P(SiMe3)2}3(THF)2] (1-Ln; Ln = La, Ce, Pr, Nd, Sm); 1-Ln was also characterized by elemental analysis; single-crystal powder X-ray diffraction; multinuclear NMR, EPR, ATR-IR, UV–vis-NIR spectroscopy; SQUID magnetometry. Breaking assumptions, observed paramagnetically broadened spectra for Ln-bound P atoms family; in solution, 1-Nd showed most downfield chemical (δ{31P} 2570.14 ppm) 1-Sm upfield value −259.21 ppm). We determined span anisotropies (CSAs) solid using magic angle spinning CSA largest 1-Pr (Ω{31P} ≈ 2000 ppm), consistent with a combination paramagnetism relatively large differences pyramidalization three solid-state. Density functional theory calculations 1-La were excellent agreement experimentally parameters. find good experimental ab initio-calculated values 1-Ln, while heavier 13C, 29Si, nuclei are not well-reproduced due current limitations contact shifts.

Language: Английский

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Unraveling the Ultrafast Photochemical Dynamics of Nitrobenzene in Aqueous Solution

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(15), P. 10407 - 10417

Published: April 4, 2024

Nitroaromatic compounds are major constituents of the brown carbon aerosol particles in troposphere that absorb near-ultraviolet (UV) and visible solar radiation have a profound effect on Earth's climate. The primary sources include biomass burning, forest fires, residential burning biofuels, an important secondary source is photochemistry aqueous cloud fog droplets. Nitrobenzene smallest nitroaromatic molecule model for photochemical behavior larger compounds. Despite obvious importance its droplet to atmospheric environment, there not been any detailed studies ultrafast dynamics nitrobenzene solution. Here, we combine femtosecond transient absorption spectroscopy, time-resolved infrared quantum chemistry calculations investigate steps following near-UV (λ ≥ 340 nm) photoexcitation nitrobenzene. To understand role surrounding water molecules nitrobenzene, compare results these investigations with analogous measurements solutions methanol, acetonitrile, cyclohexane. We find vibrational energy transfer environment quenches internal excitation, therefore, unlike gas phase, do observe evidence formation photoproducts timescales up 500 ns. also hydrogen bonding between slows S1/S0 conversion process.

Language: Английский

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SCINE—Software for chemical interaction networks

The Journal of Chemical Physics, Journal Year: 2024, Volume and Issue: 160(22)

Published: June 10, 2024

The software for chemical interaction networks (SCINE) project aims at pushing the frontier of quantum calculations on molecular structures to a new level. While individual as well simple relations between them have become routine in chemistry, developments pushed field high-throughput calculations. Chemical may be created by search specific properties design attempt, or they can defined set elementary reaction steps that form network. modules SCINE been designed facilitate such studies. features are (i) general applicability applied methodologies ranging from electronic structure (no restriction elements periodic table) microkinetic modeling (with little restrictions molecularity), full modularity so also stand-alone programs exchanged external packages fulfill similar purpose (to increase options computational campaigns and provide alternatives case tasks hard impossible accomplish with certain programs), (ii) high stability autonomous operations control steering an operator easy possible, (iii) embedding into complex heterogeneous environments taken individually context A graphical user interface unites all ensures interoperability. All components made available open source free charge.

Language: Английский

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Renormalized-Residue-Based Multireference Configuration Interaction Method for Strongly Correlated Systems

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(5), P. 1988 - 2009

Published: Feb. 21, 2024

The implementation of multireference configuration interaction (MRCI) methods in quantum systems with large active spaces is hindered by the expansion bases or intricate handling reduced density matrices (RDMs). In this work, we present a spin-adapted renormalized-residue-based MRCI (RR-MRCI) approach that leverages renormalized residues to effectively capture entanglement between and inactive orbitals. This reinforced novel efficient algorithm, which also facilitates an deployment matrix product state (MPS-MRCI). RR-MRCI framework possesses several advantages: (1) It considers orbital utilizes highly compressed MPS structure, improving computational accuracy efficiency compared internally contracted (ic) MRCI. (2) Utilizing small-sized buffer environments few external orbitals as probes based on information theory, it enhances over MPS-MRCI offers potential application molecular systems. (3) RR can be implemented conjunction ic-MRCI, eliminating need for high-rank RDMs, using distinct residues. We evaluated method across nine diverse systems, including Cu

Language: Английский

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Toward Real Chemical Accuracy on Current Quantum Hardware Through the Transcorrelated Method

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: 20(10), P. 4146 - 4160

Published: May 9, 2024

Quantum computing is emerging as a new computational paradigm with the potential to transform several research fields including quantum chemistry. However, current hardware limitations (including limited coherence times, gate infidelities, and connectivity) hamper implementation of most algorithms call for more noise-resilient solutions. We propose an explicitly correlated Ansatz based on transcorrelated (TC) approach target these major roadblocks directly. This method transfers, without any approximation, correlations from wave function directly into Hamiltonian, thus reducing resources needed achieve accurate results noisy devices. show that TC allows shallower circuits improves convergence toward complete basis set limit, providing energies within chemical accuracy experiment smaller sets and, thus, fewer qubits. demonstrate our by bond lengths, dissociation energies, vibrational frequencies close experimental hydrogen dimer lithium hydride using two four qubits, respectively. To approach's near-term potential, we perform experiments, where confirm paves way chemistry calculations already today's hardware.

Language: Английский

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Near-infrared luminescent open-shell π-conjugated systems with a bright lowest-energy zwitterionic singlet excited state

Science Advances, Journal Year: 2024, Volume and Issue: 10(30)

Published: July 24, 2024

Open-shell systems with extensive π-conjugation have fascinating properties due to their narrow bandgaps and spin interactions. In this work, we report neutral open-shell di- polyradical conjugated materials exhibiting intriguing optical magnetic properties. Our key design advance is the planarized geometry allowing for greater interaction between adjacent spins. This results in absorption emission near infrared at 803 1050 nanometers, respectively, demonstrate a unique electronic structure where bright zwitterionic excited state lowest-accessible transition. Electron paramagnetic resonance spectroscopy superconducting quantum interference device measurements reveal that our are singlets different degrees of interactions, dynamics, antiferromagnetic properties, which likely contributed formation emissive singlet near-infrared emission. addition, show reversible stable electrochromic switching more than 500 cycles, indicating potential optoelectronic electrochemical energy storage applications.

Language: Английский

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Designing Quantum Spaces of Higher Dimensionality from a Tetranuclear Erbium-Based Single-Molecule Magnet

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(33), P. 23417 - 23425

Published: Aug. 6, 2024

The spin relaxation of an Er

Language: Английский

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Ab Initio Multiple Spawning Nonadiabatic Dynamics with Different CASPT2 Flavors: A Fully Open-Source PySpawn/OpenMolcas Interface

Journal of Chemical Theory and Computation, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 4, 2024

We introduce an interface between PySpawn, a simulation package to run ab initio multiple spawning (AIMS) nonadiabatic dynamics, and OpenMolcas, software perform multiconfigurational perturbations theory (CASPT2) electronic structure calculations. Our allows us exploit all the functionalities of two codes: modular efficient Python implementation AIMS algorithm extensive analysis tools offered by with cutting-edge CASPT2 equations in including recently introduced analytical gradients different flavors. Both are fully open-source free charge, making following unique current plethora for dynamics. This represents important step toward wider application AIMS-based dynamics combined high-accuracy excited-state The importance need such demonstrated ultrafast relaxation fulvene from S

Language: Английский

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Accurate and Efficient Spin–Phonon Coupling and Spin Dynamics Calculations for Molecular Solids

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: unknown

Published: Nov. 2, 2023

Molecular materials are poised to play a significant role in the development of future optoelectronic and quantum technologies. A crucial aspect these areas is spin-phonon coupling how it facilitates energy transfer processes such as intersystem crossing, decoherence, magnetic relaxation. Thus, interest be able accurately calculate molecular spin dynamics condensed phase. Here, we demonstrate maturity ab initio methods for calculating by performing case study on single-molecule magnet showing quantitative agreement with experiment, allowing us explore underlying origins its dynamics. This feat achieved leveraging our recent developments analytic calculations conjunction new method including infinite electrostatic potential calculations. Furthermore, make first determination phonon lifetimes line widths prove that commonplace Born-Markov assumption valid, but "exact" not essential obtain accurate relaxation rates. Calculations using this approach facilitated open-source packages have developed, enabling cost-effective solids.

Language: Английский

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A call to arms: Making the case for more reusable libraries

The Journal of Chemical Physics, Journal Year: 2023, Volume and Issue: 159(18)

Published: Nov. 10, 2023

The traditional foundation of science lies on the cornerstones theory and experiment. Theory is used to explain experiment, which in turn guides development theory. Since advent computers computational algorithms, computation has risen as third cornerstone science, joining experiment an equal footing. Computation become essential part modern amending by enabling accurate comparison complicated theories sophisticated experiments, well guiding triage both design targets experiments novel methods. Like relies continued investment infrastructure: it requires hardware (the physical computer calculation run) software source code programs that performs wanted simulations). In this Perspective, I discuss present-day challenges side chemistry, arise from fast-paced programming models, hardware. argue many these could be solved with reusable open libraries, are a public good, enhance reproducibility accelerate availability state-of-the-art methods improved software.

Language: Английский

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