A5025119562- Advanced NMR Techniques and Applications
- Solid-state spectroscopy and crystallography
- Electron Spin Resonance Studies
- Atomic and Subatomic Physics Research
- Magnetic properties of thin films
- Magnetic Properties and Applications
- Synthesis and Properties of Aromatic Compounds
- Quantum, superfluid, helium dynamics
- Advanced Condensed Matter Physics
- Carbon Nanotubes in Composites
- History and advancements in chemistry
- Chemical Synthesis and Analysis
- Molecular spectroscopy and chirality
- Machine Learning in Materials Science
- Chemistry and Chemical Engineering
- Combustion and flame dynamics
- Collagen: Extraction and Characterization
- Spectroscopy and Quantum Chemical Studies
- Crystallography and Radiation Phenomena
- Thermal Radiation and Cooling Technologies
- Advanced Thermodynamic Systems and Engines
- Nuclear Physics and Applications
- Magnetic Properties and Synthesis of Ferrites
- Advanced Chemical Physics Studies
- Metallic Glasses and Amorphous Alloys
Massachusetts Institute of Technology
2022-2024
Paul Scherrer Institute
2018-2023
Wuhan University of Science and Technology
2022
Center for Integrated Quantum Science and Technology
2021
École Polytechnique Fédérale de Lausanne
2021
OmniVision Technologies (Germany)
2021
Universität Ulm
2021
Nuclear spin hyperpolarization provides a promising route to overcome the challenges imposed by limited sensitivity of nuclear magnetic resonance. Here we demonstrate that dissolution spin-polarized pentacene-doped naphthalene crystals enables transfer polarization target molecules via intermolecular cross-relaxation at room temperature and moderate fields (1.45 T). This makes it possible exploit high optically polarized crystals, while mitigating its external nuclei. With this method,...
This paper presents a study of coherent dynamic nuclear polarization (DNP) using frequency swept pulses at 94 GHz which optimize the transfer efficiency. Accordingly, an enhancement ε ∼ 496 was observed 10 mM trityl-OX063 as polarizing agent in standard 6:3:1 d8-glycerol/D2O/H2O glassing matrix 70 K. At present, this is largest DNP reported microwave and temperature. Furthermore, enhance magnetic resonance (NMR) signal reduce recycle delay, accelerating NMR acquisition.
The antisymmetric Dzyaloshinskii--Moriya interaction (DMI) plays a decisive role for the stabilization and control of chirality skyrmion textures in various magnetic systems exhibiting noncentrosymmetric crystal structure. A less studied aspect DMI is that this believed to be operative vicinity lattice imperfections crystalline materials, due local structural inversion symmetry breaking. If scenario leads an effect sizable magnitude, it implies introduces into very large class...
This paper presents a theory describing the dynamic nuclear polarization (DNP) process associated with an arbitrary frequency swept microwave pulse. The is utilized to explain integrated solid effect (ISE) as well newly discovered stretched (SSE) and adiabatic (ASE). It verified experiments performed at 9.4 GHz (0.34 T) on single crystals of naphthalene doped pentacene-d14. shown that SSE ASE can be more efficient than ISE. Furthermore, predicts efficiency improves high magnetic fields,...
We propose a mechanism for dynamic nuclear polarization that is different from the well-known Overhauser effect, solid cross and thermal mixing processes. term it Resonant Mixing (RM), we show arises evolution of density matrix simple electron-nucleus coupled spin pair subject to weak microwave irradiation, same interactions as effect. However, SE optimal when field off-resonance, whereas RM on-resonance involves states by together with electron-nuclear coupling. Finally, argue this...
There is a fundamental issue with the use of dynamic nuclear polarization (DNP) to enhance spin polarization: same polarizing agent (PA) needed for DNP also responsible shortening lifetime hyperpolarization. As result, long-term storage and transport hyperpolarized samples severely restricted apparatus necessarily located near or integrated using spins. In this paper, we demonstrate that naphthalene single crystals can serve as long-lived reservoir proton be exploited signals in benchtop...
A general theory is presented describing the photo-excitation dynamics of transient, paramagnetic triplet states aromatic molecules including their absorption properties in a molecular host crystal when irradiated by pulsed laser beam. It applied to system pentacene doped naphthalene single crystal, where results highly non-equilibrium population intermediate electronic states. These can be addressed align proton spins at moderate experimental conditions using dynamic nuclear polarisation...
Substitutional nitrogen impurities within the diamond lattice, known as P1 centers, have unpaired electrons that can mediate microwave driven dynamic nuclear polarization (DNP). In this paper we explore DNP of bulk
Nuclear spin hyperpolarization provides a promising route to overcome the challenges imposed by limited sensitivity of nuclear magnetic resonance. Here we demonstrate that dissolution spin-polarized pentacene-doped naphthalene crystals enables transfer polarization target molecules via intermolecular cross relaxation at room temperature and moderate fields (1.45$\,$T). This makes it possible exploit high optically polarized while mitigating its external nuclei, particularly large distances...
The Dzyaloshinskii-Moriya interaction (DMI), which typically occurs in lattices without space inversion symmetry, can also be induced a highly symmetric lattice by local symmetry breaking due to any defect. We recently presented an experimental study of polarized small angle neutron scattering (SANS) on the nanocrystalline soft magnet Vitroperm (Fe73Si16B7Nb3Cu1), where interface between FeSi nanoparticles and amorphous magnetic matrix serves as such SANS cross sections exhibited...
Abstract We present the status of development a novel neutron spin filter based on strong dependence scattering protons. Using photo-excited triplet states for dynamic nuclear polarization (DNP) process, proton values 80% can now be achieved in pentacene doped single crystals naphthalene at field 0.36 T simple helium flow cryostat. Careful sample preparation lead to extremely long decay times under moderate conditions that allowed us develop transportable device. The is polarized lab well...
We propose a new mechanism for dynamic nuclear polarization that is different from the well-known Overhauser effect, solid cross effect and thermal mixing processes. In particular, we discovered evolution of density matrix with simple Hamiltonian coupled electron-nuclear spin pair weak microwave irradiation yields enhancement when irradiating near electron Larmor frequency. denote as Resonant Mixing (RM). believe this responsible observed dispersive shaped DNP field profile trityl samples...
The Dzyaloshinskii-Moriya interaction (DMI) is believed to be operative in low-symmetry crystal structures lacking space-inversion symmetry. However, already 1963, Arrott pointed out that even a high-symmetry lattice, where the DMI would normally vanish, this present vicinity of any lattice defect. Based on these considerations and recent theoretical work, first experimental studies impact spin-polarized magnetic small-angle neutron scattering (SANS) polycrystalline magnets exhibiting large...
The use of polarized protons as a broad-band neutron spin filter is an attractive alternative to the well-established polarization techniques, namely 3 He gas and super mirrors, since spin-dependent proton scattering cross-section large in broad wavelength range. We have developed novel where we create necessary solid with recent method dynamic nuclear (DNP) that uses photo-excited triplet states. This requires only moderate experimental means allows compact design. In order quantify...
Collagen-mimetic peptides (CMP) have been invaluable tools for understanding the structure and function of collagen, which is most abundant protein in animals. CMPs also developed as probes that detect damaged collagen because specificity required to form a triple helix. These are not, however, ratiometric. Here, we used EPR spectroscopy determine end-to-end distances do not stable homotrimeric helices. We found those shorter than context helix, suggesting their potential utility "molecular...
It has been known for decades that a ferromagnetic sample can depolarize transmitted neutron beam. This effect was used and developed into the neutron-depolarization technique to investigate magnetic structure of materials. Since polarization evolves continuously as neutrons move through sample, initial spin states on scattering will be different at depths within sample. leads contamination measured spin-dependent neutron-scattering intensities by other cross sections. The rarely considered...
This paper presents a study of coherent dynamic nuclear polarization (DNP) using frequency swept pulses at 94 GHz which optimize the transfer efficiency. Accordingly, an enhancement ℇ∼496 was observed 10mM trityl-OX063 as polarizing agent in standard d8-glycerol:D2O:H2O :: 6:3:1 glassing matrix 70K. At present this is largest DNP reported microwave and temperature. Furthermore, enhance magnetic resonance (NMR) signal reduce recycle delay, accelerating NMR acquisition.
This paper presents a theory describing the dynamic nuclear polarization (DNP) process associated with an arbitrary frequency swept microwave pulse. The is utilized to explain integrated solid effect (ISE) as well newly discovered stretched (SSE) and adiabatic (ASE). It verified experiments performed at 9.4 GHz (0.34 T) on single crystals of naphthalene doped pentacene-d14. shown that SSE ASE can be more efficient than ISE. Furthermore, predicts efficiency improves high magnetic fields,...