Topic
Relaxation (NMR)
About: Relaxation (NMR) is a research topic. Over the lifetime, 29342 publications have been published within this topic receiving 689851 citations.
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113 citations
TL;DR: A new theoretical argument and a study of the temperature-dependent relaxation dynamics of helium show that defects may play an important role in describing its supersolid behavior, and provides evidence for a “supersolid glass,” where glassy behavior of crystal dislocations and superfluidity can coexist.
Abstract: Although solid helium-4 (4He) may be a supersolid, it also exhibits many phenomena unexpected in that context We studied relaxation dynamics in the resonance frequency f(T) and dissipation D(T) of a torsional oscillator containing solid 4He With the appearance of the “supersolid” state, the relaxation times within f(T) and D(T) began to increase rapidly together More importantly, the relaxation processes in both D(T) and a component of f(T) exhibited a complex synchronized ultraslow evolution toward equilibrium Analysis using a generalized rotational susceptibility revealed that, while exhibiting these apparently glassy dynamics, the phenomena were quantitatively inconsistent with a simple excitation freeze-out transition because the variation in f was far too large One possibility is that amorphous solid 4He represents a new form of supersolid in which dynamical excitations within the solid control the superfluid phase stiffness
113 citations
TL;DR: In this article, the magnetic field and temperature dependence of the rates for all two-body spin exchange and dipolar transitions among hyperfine levels in cryogenic H gas was calculated by means of the coupled-channels method.
Abstract: We calculate the magnetic field and temperature dependence of the rates for all two-body spin-exchange and dipolar transitions among hyperfine levels in cryogenic H gas by means of the coupled-channels method. A description of this method and its practical application is presented. A simple interpretation of the rates is given, in some cases with associated simple closed-form formulas, based on the degenerate-internal-states approximation.
113 citations
TL;DR: In this paper, the sensitivity of nitrogen-15-proton gradient-selected HSQC spectra of proteins dissolved in H2O is compromised due to exchange between the NH and the water protons.
113 citations
TL;DR: In this paper, the Raman spectra for the excitation of single vibronic levels of the first excited singlet state of azulene in a naphthalene mixed crystal at 2 K are described.
Abstract: Resonance fluorescence and Raman spectra for excitation of single vibronic levels of the first excited singlet state of azulene in a naphthalene mixed crystal at 2 K are described. The intensity distributions for the resonance emission spectra were used to verify and in some cases reassign previously proposed correlations of the ground and excited state a1 modes. Relaxed fluorescence from levels populated via vibrational relaxation from the resonant vibronic level was observed and measurements of the population ratios for the vibronic levels relative to the zero‐point level are given. From these ratios the following two conclusions were made. (1) In addition to the zero‐point level, only strongly absorbing nearby vibronic levels are significantly populated through vibrational relaxation from the resonantly pumped level for excitations up to ≈1560 cm−1 above the zero‐point level. This suggests that there is little cascading within the S1 vibrational manifold and that vibrational relaxation occurs largely b...
113 citations