Nuclear magnetic and dielectric spectroscopy of amorphous ice

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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.