Nuclear magnetic and dielectric spectroscopy of amorphous ice

非晶冰的核磁和介电谱

• 批准号: 413265854
• 负责人: Professor Dr. Roland Böhmer
• 金额: --
• 依托单位: Lehrstuhl für Experimentelle Physik III
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/413265854?language=en
• 关键词: Nuclear; magnetic; dielectric; spectroscopy; amorphous

On the surface of interstellar dust, water can condense as non-crystalline, so called amorphous or glassy ice. This form of ice – i.e., the non-crystalline one – appears to be the most abundant in outer space. Furthermore, in addition to the large number of crystalline ice phases, several glassy states exist that can differ in density by up to one third. Upon heating, low-density and high-density amorphous ices, as prepared in the laboratory, transform to controversially discussed states of matter near glass transition temperatures of –135 °C or lower. Via the study of pure, doped, gas-filled, as well as isotope-labeled modifications of various non-crystalline states of ice, it is the goal of this project to explore the extent to which rotational as well as translational degrees of freedom contribute to these glass transitions. To this end frequency-domain and in particular time-domain dielectric measurements will be employed as well as oxygen-17 magnetic resonance spectroscopy, thus methods that provide complementary handles on molecular motions in ultracold water.

在星际尘埃的表面，水可以凝结成非结晶体，即所谓的无定形或玻璃状冰。这种形式的冰——即非结晶冰——似乎是外太空中最丰富的。此外，除了大量的结晶冰相之外，还存在几种密度相差高达三分之一的玻璃态。实验室制备的低密度和高密度无定形冰在加热后会转变为接近 –135 °C 或更低玻璃化转变温度的有争议的物质状态。通过研究冰的各种非晶态的纯、掺杂、充气以及同位素标记的修饰，该项目的目标是探索旋转和平移自由度对这些玻璃化转变的贡献程度。为此，将采用频域、特别是时域介电测量以及氧 17 磁共振波谱，从而提供对超冷水中分子运动的补充处理的方法。