Hoffmann Lars, Beerwerth Joachim, Adjei-Körner Mischa, Fuentes-Landete Violeta, Tonauer Christina M, Loerting Thomas, Böhmer Roland
Fakultät Physik, Technische Universität Dortmund, 44221 Dortmund, Germany.
Institute of Physical Chemistry, University of Innsbruck, Innrain 52c, A-6020 Innsbruck, Austria.
J Chem Phys. 2022 Feb 28;156(8):084503. doi: 10.1063/5.0080333.
Using oxygen-17 as a nuclear probe, spin relaxometry was applied to study the high-density and low-density states of amorphous ice, covering temperatures below and somewhat above their glass transitions. These findings are put in perspective with results from deuteron nuclear magnetic resonance and with calculations based on dielectrically detected correlation times. This comparison reveals the presence of a wide distribution of correlation times. Furthermore, oxygen-17 central-transition echo spectra were recorded for wide ranges of temperature and pulse spacing. The spectra cannot be described by a single set of quadrupolar parameters, suggesting a distribution of H-O-H opening angles that is broader for high-density than for low-density amorphous ice. Simulations of the pulse separation dependent spin-echo spectra for various scenarios demonstrate that a small-step frequency diffusion process, assigned to the presence of homonuclear oxygen-oxygen interactions, determines the shape evolution of the pulse-separation-dependent spectra.
使用氧-17作为核探针，自旋弛豫测量法被用于研究非晶冰的高密度和低密度状态，涵盖低于和略高于其玻璃化转变温度的范围。这些发现与氘核磁共振结果以及基于介电检测相关时间的计算结果相结合进行考量。这种比较揭示了存在广泛分布的相关时间。此外，记录了宽温度范围和脉冲间距下的氧-17中心跃迁回波光谱。这些光谱不能用单一组四极参数来描述，这表明高密度非晶冰的H - O - H键角分布比低密度非晶冰更宽。针对各种情况对脉冲分离依赖的自旋回波光谱进行模拟表明，一种归因于同核氧-氧相互作用存在的小步长频率扩散过程决定了脉冲分离依赖光谱的形状演变。
