نتایج جستجو برای: parahydrogen
تعداد نتایج: 287 فیلتر نتایج به سال:
NMR signal amplification by reversible exchange (SABRE) is a NMR hyperpolarization technique that enables nuclear spin polarization enhancement of molecules via concurrent chemical exchange of a target substrate and parahydrogen (the source of spin order) on an iridium catalyst. Recently, we demonstrated that conducting SABRE in microtesla fields provided by a magnetic shield enables up to 10% ...
The photochemistry of the chelated enol form of acetylacetone (AcAc) was investigated by UV excitation of the S(2) state at 266 nm in parahydrogen matrices, complemented by experiments in neon and normal hydrogen matrices. Infrared (IR) spectroscopy, combined with theoretical calculations, was used to identify the photoproducts. Isomerization towards various non-chelated forms (no intramolecula...
Hyperpolarization produces nuclear spin polarization that is several orders of magnitude larger than that achieved at thermal equilibrium thus providing extraordinary contrast and sensitivity. As a parahydrogen induced polarization (PHIP) technique that does not require chemical modification of the substrate to polarize, Signal Amplification by Reversible Exchange (SABRE) has attracted a lot of...
Here we demonstrate how parahydrogen can be used to prepare a two-spin system in an almost pure state which is suitable for implementing nuclear magnetic resonance quantum computation. A 12 ns laser pulse is used to initiate a chemical reaction involving pure parahydrogen (the nuclear spin singlet of H2). The product, formed on the micros time scale, contains a hydrogen-derived two-spin system ...
Introduction Parahydrogen induced polarization (PHIP) has turned out to be a versatile technique to obtain hyperpolarized molecules exhibiting strong NMR signals via a chemical approach. PHIP makes use of breaking the high initial symmetry of parahydrogen during homogeneously catalyzed hydrogenations of unsaturated substrates and, therefore, of the creation of nonequivalent protons in the produ...
The diffusion and reactivity of hydrogen atoms in solid parahydrogen at temperatures between 1.5 K 4.3 are investigated by high-resolution infrared spectroscopy. Hydrogen produced within as the by-products 193 nm situ photolysis N2O, which induces a two-step tunneling reaction, H + N2O ? cis-HNNO trans-HNNO. second-order rate constant for first step to form is found be inversely proportional co...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید