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| Open AccessAmino acid gas phase circular dichroism and implications for the origin of biomolecular asymmetry
Chiroptical properties of amino acids are challenging to investigate in the gas phase due to the low vapor pressure of these molecules. Here the authors succeed in measuring circular dichroism active transitions and anisotropies in the ultraviolet range for several gas-phase amino acids, shedding light on the interactions between molecules and circularly polarized light that lead to chiral symmetry breaking.
- Cornelia Meinert
- , Adrien D. Garcia
- & Uwe J. Meierhenrich
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Article
| Open AccessControlling the helicity of π-conjugated oligomers by tuning the aromatic backbone twist
One approach to altering the properties of π-conjugated oligomers is conformational engineering, in which the degree of rotation around the bonds linking monomers is restricted. Here the authors apply the conformational engineering approach on individual monomers using tethers of varying lengths to twist the aromatic units, and study the effects of varying the angles.
- Anjan Bedi
- , Amit Manor Armon
- & Ori Gidron
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| Open AccessExperimental identification of aminomethanol (NH2CH2OH)—the key intermediate in the Strecker Synthesis
The Strecker synthesis is considered a viable route to amino acids formation on the primordial Earth. Here the authors succeed in observing its elusive intermediate aminomethanol, formed by insertion of an electronically excited oxygen atom in methylamine and stabilized by an icy matrix, using isomer-selective photoionization time-of-flight mass spectrometry during thermal desorption of the ice mixture.
- Santosh K. Singh
- , Cheng Zhu
- & Ralf I. Kaiser
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| Open AccessMapping the broadband circular dichroism of copolymer films with supramolecular chirality in time and space
Time-resolved circular dichroism spectra can reveal changes in chirality on ultrashort time scales, but achieving sub-picosecond time resolution is still a challenge. Here the authors demonstrate 100-femtosecond time-resolved CD mapping of polyfluorene copolymer thin films, revealing a supramolecular origin of their chiroptical response.
- Marius Morgenroth
- , Mirko Scholz
- & Thomas Lenzer
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| Open AccessFollowing excited-state chemical shifts in molecular ultrafast x-ray photoelectron spectroscopy
Imaging the charge flow in photoexcited molecules would provide key information on photophysical and photochemical processes. Here the authors demonstrate tracking in real time after photoexcitation the change in charge density at a specific site of 2-thiouracil using time-resolved X-ray photoelectron spectroscopy.
- D. Mayer
- , F. Lever
- & M. Gühr
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| Open AccessEvolution of microscopic heterogeneity and dynamics in choline chloride-based deep eutectic solvents
Tailoring the macroscopic properties of deep eutectic solvents requires knowing how these depend on the local structure and microscopic dynamics. The authors, with computational and experimental tools spanning a wide range of space- and timescales, shed light into the relationship between micro and macroscopic properties in glyceline and ethaline.
- Stephanie Spittle
- , Derrick Poe
- & Joshua Sangoro
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| Open AccessTracking excited state decay mechanisms of pyrimidine nucleosides in real time
The photophysical mechanism by which nucleosides dissipate energy after UV light irradiation is still under debate. Here the authors, using ultrafast time resolved optical spectroscopies and quantum chemical computations, resolve the early steps of such mechanism in uridine and 5-methyluridine in aqueous solution.
- Rocío Borrego-Varillas
- , Artur Nenov
- & Giulio Cerullo
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Article
| Open AccessA different perspective for nonphotochemical quenching in plant antenna complexes
Nonphotochemical quenching (NPQ) protects photosynthetic complexes from damage due to excess light. Here the authors explore different conformations of the plant CP29 light harvesting complex, showing how protein tuning of carotenoid excitation energies and carotenoid-chlorophyll interactions account for NPQ.
- Edoardo Cignoni
- , Margherita Lapillo
- & Benedetta Mennucci
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| Open AccessObservation of the ponderomotive effect in non-valence bound states of polyatomic molecular anions
The ponderomotive effect experienced by electrons in a molecule under a transient electric field impacts the reactivity, but has been difficult to detect. The authors observe a ponderomotive force on the excess quasi-free electron in the non-valence bound state of three molecular anions, by measuring the photodetachment spectrum under irradiation with a non-resonant wavelength.
- Do Hyung Kang
- , Jinwoo Kim
- & Sang Kyu Kim
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Article
| Open AccessFreezing of few nanometers water droplets
Ice nucleation in confined geometries is a ubiquitous phenomenon, but difficult to characterize. Here the authors investigate experimentally the freezing of water nanodroplets surrounded by octane in nanopores down to 2 nm, and demonstrate that the soft curved oil-water interface suppresses heterogeneous ice nucleation, which occurs at a lower temperature than homogenous bulk nucleation.
- Alireza Hakimian
- , Mohammadjavad Mohebinia
- & Hadi Ghasemi
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Article
| Open AccessRoom-temperature dynamic nuclear polarization enhanced NMR spectroscopy of small biological molecules in water
Dynamic nuclear polarization (DNP) greatly improves the NMR sensitivity, but its implementation in aqueous solutions is challenging. Here the authors demonstrate carbon polarization enhancement via in situ Overhauser DNP in small biomolecules in water at room temperature and high magnetic field.
- Danhua Dai
- , Xianwei Wang
- & Jiafei Mao
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Article
| Open AccessMolecular-level insights into the electronic effects in platinum-catalyzed carbon monoxide oxidation
A molecular-level understanding of the electronic effects remains a grand challenge in heterogeneous catalysis. Here, the authors report an unconventional kinetics strategy for bridging the upscaling gap between the microscopic fingerprints of active sites and the macroscopic catalytic performance.
- Wenyao Chen
- , Junbo Cao
- & Xuezhi Duan
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Article
| Open AccessResolving sub-angstrom ambient motion through reconstruction from vibrational spectra
Tracking single molecule movements is a challenging task, but highly desired for applications and fundamental studies. Here the authors reconstruct the sub-angstrom relative movements of a molecule interacting with a metal adatom, by measuring its vibrational spectrum in a self-assembled monolayer, continuously modified by the adatom in a nanoparticle-on-mirror construct.
- Jack Griffiths
- , Tamás Földes
- & Jeremy J. Baumberg
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| Open AccessSurvival of polycyclic aromatic hydrocarbon knockout fragments in the interstellar medium
Ion storage rings allow reactions to be studied over orders of magnitude in time, bridging the gap between typical experimental and astronomical timescales. Here the authors observe that polycyclic aromatic hydrocarbon fragments produced upon collision with He atoms at velocities typical of stellar winds and supernova shockwaves remain intact up to second timescales, thus may play an important role in interstellar chemistry.
- Michael Gatchell
- , João Ameixa
- & Henning Zettergren
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Article
| Open AccessCharging and ultralong phosphorescence of lanthanide facilitated organic complex
Compounds featuring long-lived luminescence have potential applications in a variety of fields, including anti-counterfeiting and switches. Here the authors report a lanthanide-based compound that exhibits phosphorescence observable by the naked eye for up to 30 s at 77 K; On-off continuous irradiation cycles reveal a charging behaviour associated with triplet-triplet absorption, showing a shorter rise lifetime than the decay lifetime.
- Waygen Thor
- , Yue Wu
- & Ka-Leung Wong
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Article
| Open AccessMicrocavity-like exciton-polaritons can be the primary photoexcitation in bare organic semiconductors
Exciton-polaritons are typically formed in organic systems when the molecules are confined between metallic or dielectric mirrors. Here, the authors reveal that interactions between excitons and moderately confined photonic states within the bare organic film can also lead to polariton formation, making them the primary photoexcitation.
- Raj Pandya
- , Richard Y. S. Chen
- & Akshay Rao
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Article
| Open AccessRapid oxygen exchange between hematite and water vapor
Knowing how individual water molecules interact with surfaces is crucial for understanding surface and interface phenomena. Here, the authors show how local water-water interactions enable an unforeseen and surprisingly rapid mechanism of atom exchange between a common mineral and its surroundings.
- Zdenek Jakub
- , Matthias Meier
- & Gareth S. Parkinson
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| Open AccessMonovalent lanthanide(I) in borozene complexes
The most common oxidation state for lanthanides is +3. Here the authors use photoelectron spectroscopy and theoretical calculations to study half-sandwich complexes where a lanthanide center in the oxidation state +1 is bound to an aromatic wheel-like B82- ligand.
- Wan-Lu Li
- , Teng-Teng Chen
- & Lai-Sheng Wang
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| Open AccessOptical deciphering of multinary chiral compound mixtures through organic reaction based chemometric chirality sensing
The stereoselective analysis of mixtures of chiral compounds typically requires time-consuming chromatography. Here, the authors combine reaction based chiroptical sensing and chemometric tools to directly determine the absolute configuration, enantiomeric composition and concentration of convoluted samples without physical separation.
- Diandra S. Hassan
- & Christian Wolf
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| Open AccessMarcus inverted region of charge transfer from low-dimensional semiconductor materials
Marcus inverted region for charge transfer from low-dimensional semiconductor materials has been long sought after. Here, the authors reveal this region by directly measuring charge transfer from single-charge states rather than excitonic states.
- Junhui Wang
- , Tao Ding
- & Kaifeng Wu
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| Open AccessVibrationally excited molecular hydrogen production from the water photochemistry
Understanding the source of vibrationally excited molecular hydrogen is an essential prerequisite for understanding the chemical evolution in the universe. Here the authors report a photodissociation pathway to produce vibrationally excited H2 via the water photochemistry.
- Yao Chang
- , Feng An
- & Xueming Yang
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Article
| Open AccessSustained enzymatic activity and flow in crowded protein droplets
Living cells can harvest environmental energy to drive chemical processes. Here the authors design a minimal artificial system that achieves steady states at similar metabolic densities to microorganisms.
- Andrea Testa
- , Mirco Dindo
- & Paola Laurino
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Article
| Open AccessNormal & reversed spin mobility in a diradical by electron-vibration coupling
In this manuscript, Negri, Zheng, Casado et al develop a stable and flexible diradical. Using a combination of experimental and theoretical techniques, they show how heating leads to change in the electronic and spin delocalizations ocurring between quinoidal and aromatic forms, and elucidate a unique spin-vibrational coupling.
- Yi Shen
- , Guodong Xue
- & Juan Casado
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Article
| Open AccessTime-resolved relaxation and fragmentation of polycyclic aromatic hydrocarbons investigated in the ultrafast XUV-IR regime
Polycyclic aromatic hydrocarbons play an important role in interstellar chemistry, where interaction with high energy photons can induce ionization and fragmentation reactions. Here the authors, with XUV-IR pump-probe experiments, investigate the ultrafast photoinduced dynamics of fluorene, phenanthrene and pyrene, providing insight into their preferred reaction channels.
- J. W. L. Lee
- , D. S. Tikhonov
- & M. Schnell
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Article
| Open AccessConformer-specific polar cycloaddition of dibromobutadiene with trapped propene ions
Identifying a concerted or stepwise mechanism in Diels–Alder reactions is experimentally challenging. Here the authors demonstrate the coexistence of both mechanisms in the reaction of 2,3-dibromobuta-1,3-diene with propene ions, using a conformationally controlled molecular beam reacting with trapped ions and ab initio computations
- Ardita Kilaj
- , Jia Wang
- & Stefan Willitsch
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| Open AccessBiomimetic CO oxidation below −100 °C by a nitrate-containing metal-free microporous system
CO oxidation is of importance both for inorganic and living systems. Here the authors demonstrate that CO can be oxidized by nitrate in small-pore SSZ-13 zeolite at a temperature below −100 °C using spectroscopy and density functional theory calculations.
- Konstantin Khivantsev
- , Nicholas R. Jaegers
- & Janos Szanyi
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Article
| Open AccessThe Hsc70 disaggregation machinery removes monomer units directly from α-synuclein fibril ends
Molecular chaperones from the Hsp70 family can break up protein aggregates, including amyloids. Here, the authors utilize microfluidic diffusional sizing to assess the mechanism of α-synuclein (αS) disaggregation by the Hsc70–DnaJB1–Apg2 system, and show that single αS molecules are removed directly from the fibril ends.
- Matthias M. Schneider
- , Saurabh Gautam
- & Tuomas P. J. Knowles
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| Open AccessQuantification of the Li-ion diffusion over an interface coating in all-solid-state batteries via NMR measurements
Development of all-solid-state batteries requires stable solid electrolyte-electrode interfaces. Here, via exchange-NMR measurements, the authors investigate the positive electrode-solid electrolyte interface, revealing the impact of an inorganic coating on the Li-ion transport properties.
- Ming Liu
- , Chao Wang
- & Marnix Wagemaker
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Article
| Open AccessVisualizing designer quantum states in stable macrocycle quantum corrals
Creating atomically-precise quantum architectures with high digital fidelity and desired quantum states is an important goal for quantum technology applications. Here the authors devise an on-surface synthetic protocol to construct atomically-precise covalently linked organic quantum corrals with the formation of a series of new quantum resonance states.
- Xinnan Peng
- , Harshitra Mahalingam
- & Jiong Lu
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| Open AccessAtomic level fluxional behavior and activity of CeO2-supported Pt catalysts for CO oxidation
In heterogeneous catalysts, the nature of the atomic-scale dynamics taking place at nanoparticle surfaces during catalysis is not understood. Here, we employ electron microscopy to show that activity directly correlates with fluxional behavior of the surface and interface atoms.
- Joshua L. Vincent
- & Peter A. Crozier
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Article
| Open AccessTwo-dimensional monolayer salt nanostructures can spontaneously aggregate rather than dissolve in dilute aqueous solutions
Aqueous solutions under nanoscale confinement exhibit interesting physicochemical properties. This work reports evidence on the spontaneous formation of two-dimensional alkali chloride crystalline/non-crystalline nanostructures in dilute aqueous solution under nanoscale confinement by computer simulations.
- Wenhui Zhao
- , Yunxiang Sun
- & Xiao Cheng Zeng
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| Open AccessLocal-electrostatics-induced oxygen octahedral distortion in perovskite oxides and insight into the structure of Ruddlesden–Popper phases
The authors observe two-dimensional shear faults in five different perovskite-type materials and detailed structures of more than 80 oxides and halides to elucidate an electrostatic origin for Jahn–Teller-type tetragonal distortion of oxygen octahedra.
- Youngjae Hong
- , Pilgyu Byeon
- & Sung-Yoon Chung
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| Open AccessIdentification of a prismatic P3N3 molecule formed from electron irradiated phosphine-nitrogen ices
High-nitrogen content polyhedral molecules are of fundamental interest for theory and for synthesis applications. The authors, using isomer selective, tunable soft photoionization reflectron time-of-flight mass spectrometry, identify the formation of a hitherto elusive prismatic P3N3 molecule during sublimation of PH3 and N2 ice mixtures exposed to energetic electrons.
- Cheng Zhu
- , André K. Eckhardt
- & Ralf I. Kaiser
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| Open AccessQuantum state tomography of molecules by ultrafast diffraction
Ultrafast diffraction is fundamental in capturing the structural dynamics of molecules. Here, the authors establish a variant of quantum state tomography for arbitrary degrees of freedom to characterize the molecular quantum states, which will enable the reconstruction of a quantum molecular movie from diffraction data.
- Ming Zhang
- , Shuqiao Zhang
- & Zheng Li
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| Open AccessRelief of excited-state antiaromaticity enables the smallest red emitter
Commonly, large π-conjugated systems facilitate low-energy electronic transitions. Here, the authors demonstrate that the relief of excited-state antiaromaticity of the benzene core leads to large Stokes shifts, and allows the construction of emitters covering the entire visible spectrum without the need of extending π-conjugation.
- Heechan Kim
- , Woojin Park
- & Dongwhan Lee
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| Open AccessSpectroscopic glimpses of the transition state of ATP hydrolysis trapped in a bacterial DnaB helicase
Here, the authors use solid-state NMR and EPR measurements to characterise the ATP hydrolysis transition state of the oligomeric bacterial DnaB helicase from Helicobacter pylori, which was trapped by using aluminium fluoride as a chemical mimic. They identify protein protons that coordinate to the phosphate groups of ADP and DNA and observe that the aluminium fluoride unit is highly mobile and fast-rotating.
- Alexander A. Malär
- , Nino Wili
- & Thomas Wiegand
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| Open AccessDEEP picker is a deep neural network for accurate deconvolution of complex two-dimensional NMR spectra
The analysis of NMR spectra of complex biochemical samples with respect to individual resonances is challenging but critically important. Here, the authors present a deep learning-based method that accelerates this process also for crowded NMR data that are non-trivial to analyze, even by expert NMR spectroscopists.
- Da-Wei Li
- , Alexandar L. Hansen
- & Rafael Brüschweiler
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| Open AccessCarbon clusters formed from shocked benzene
Shock-wave driven reactions of organic molecules may have played a key role in prebiotic chemistry, but their mechanisms are difficult to investigate. The authors, using time-resolved x-ray diffraction and small-angle x-ray scattering experiments, observe the transformation of liquid benzene during a shock, identifying carbon and hydrocarbon solid products.
- D. M. Dattelbaum
- , E. B. Watkins
- & R. L. Sandberg
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Article
| Open AccessVacancy control in acene blends links exothermic singlet fission to coherence
A complete understanding of singlet fission (SF) in molecular materials will enable the design of optimised optoelectronic devices. Here, the authors use vacancy control in acene-based blends to link coherent and incoherent SF pathways to energetics.
- Clemens Zeiser
- , Chad Cruz
- & Katharina Broch
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Article
| Open AccessX-ray transient absorption reveals the 1Au (nπ*) state of pyrazine in electronic relaxation
Radiationless relaxation is ubiquitous in natural processes and often involves excited states that are difficult to observe. Here the authors, combining X-ray transient absorption spectroscopy and computations, provide insight into the photoinduced dynamics in pyrazine and the involvement of an optically dark 1Au(nπ*) state.
- Valeriu Scutelnic
- , Shota Tsuru
- & Stephen R. Leone
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| Open AccessFilming ultrafast roaming-mediated isomerization of bismuth triiodide in solution
The roaming reaction is a common process in the gas phase and in solution, but observation of the involved atomic movements has been challenging. The authors, using femtosecond time-resolved X-ray liquidography, resolve the detailed structural dynamics at the onset of a roaming reaction in the photoinduced isomerization of BiI3 in solution.
- Eun Hyuk Choi
- , Jong Goo Kim
- & Hyotcherl Ihee
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Article
| Open AccessInterplay of mechanics and chemistry governs wear of diamond-like carbon coatings interacting with ZDDP-additivated lubricants
Wear reduction in diamond-like carbon interacting with ZDDP-additivated oils is essential for current automotive applications. Here, the authors present an atomic-scale study revealing that this can be achieved by tailoring diamond-like carbon’s stiffness, surface nano-topography, and hydrogen content.
- Valentin R. Salinas Ruiz
- , Takuya Kuwahara
- & Maria-Isabel de Barros Bouchet
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Article
| Open AccessVisualization of gaseous iodine adsorption on single zeolitic imidazolate framework-90 particles
Zeolitic imidazolate frameworks are promising as high-capacity iodine adsorbents. Here the authors image the gaseous I2 adsorption on single ZIF-90 particles, clarifying the inter-particle heterogeneity in adsorption reactivity and performance improvement after introduction of linker defects .
- Yuting Lei
- , Guihua Zhang
- & Yi He
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Article
| Open AccessRotational and nuclear-spin level dependent photodissociation dynamics of H2S
The photodissociation dynamics of small molecules in the vacuum ultraviolet range can have key implications for astrochemical modelling, but revealing such dynamical details is a challenging task. Here the authors, combining high resolution experimental techniques, provide a detailed description of the fragmentation dynamics of selected rotational levels of a predissociated Rydberg state of H2S.
- Yarui Zhao
- , Zijie Luo
- & Xueming Yang
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Article
| Open AccessNanoscale cooperative adsorption for materials control
Adsorption is a fundamentally important process but challenging to quantify, especially at the nanoscale. Here, the authors map the adsorption affinity and cooperativity of various ligands on single gold nanoparticles and discover adsorption crossover behaviors between different facets, leading to a strategy to control particle shape.
- Rong Ye
- , Ming Zhao
- & Peng Chen
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Article
| Open AccessLiquid flow reversibly creates a macroscopic surface charge gradient
Reactions at the interface between mineral surfaces and flowing liquids are ubiquitous in nature. Here the authors explore, using surface-specific sum frequency generation spectroscopy and numeric calculations, how the liquid flow affects the charging and dissolution rates leading to flow-dependent charge gradients along the surface.
- Patrick Ober
- , Willem Q. Boon
- & Mischa Bonn
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Article
| Open AccessFast-field-cycling ultralow-field nuclear magnetic relaxation dispersion
Nuclear spin polarization and relaxation can be studied using nuclear magnetic resonance (NMR). Here the authors demonstrate a combination of fast-field cycling and optical magnetometry techniques, to realize a NMR sensor that operates in the region of very low frequency and high relaxation rate.
- Sven Bodenstedt
- , Morgan W. Mitchell
- & Michael C. D. Tayler
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| Open AccessUbiquitous organic molecule-based free-standing nanowires with ultra-high aspect ratios
Extension of nanostructure fabrication in the single-nm regime is a promising but fabrication of nanostructures with high aspect ratios remains challenging. Here, the authors use high energy charged particles to produce free-standing 1D organic nanostructures with extremely high aspect ratios and controlled number density.
- Koshi Kamiya
- , Kazuto Kayama
- & Shu Seki