Scaling of Rotational Constants.

This manuscript introduces the concept of scaling factors for rotational constants. These factors are designed to bring computed equilibrium rotational constants closer to experimentally fitted ground-state-averaged rotational constants. The parameterization of the scaling factors was performed for several levels of theory, namely DF-D/def2-VP (DF=B3LYP,PBE0, n=3(BJ),4, m=S,TZ), PBEh-3c, and r⁢2SCAN-3c.

Enthalpy Change from Pure Cubic Ice I to Hexagonal Ice I.

The preparation of pure cubic ice without hexagonal stacking faults has been realized only recently by del Rosso et al. ( 2020, 19, 663-668) and Komatsu et al. ( 2020, 11, 464).

Nucleation and growth of crystalline ices from amorphous ices.

We here review mostly experimental and some computational work devoted to nucleation in amorphous ices. In fact, there are only a handful of studies in which nucleation and growth in amorphous ices are investigated as two separate processes. In most studies, crystallization temperatures T or crystallization rates R are accessed for the combined process.

Infrared Spectroscopy on Equilibrated High-Density Amorphous Ice.

High-density (HDA) and low-density amorphous ices (LDA) are believed to be counterparts of the high- and low-density liquid phases of water, respectively. In order to better understand how the vibrational modes change during the transition between the two solid states, we present infrared spectroscopy measurements, following the change of the decoupled OD-stretch () (∼2460 cm) and OH-combinational mode ( + , + 2) (∼5000 cm). We observe a redshift from HDA to LDA, accompanied with a drastic decrease of the bandwidth.

Isotope effects on the dynamics of amorphous ices and aqueous phosphoric acid solutions.

The glass transitions of amorphous ices as well as of aqueous phosphoric acid solutions were reported to display very large H/H isotope effects. Using dielectric spectroscopy, in both types of glassformers for equimolar protonated/deuterated mixtures an almost ideal isotope-mixing behavior rather than a bimodal relaxation is found. For the amorphous ices this finding is interpreted in terms of a glass-to-liquid rather than an orientational glass transition scenario.

Oxygen NMR of high-density and low-density amorphous ice.

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.

The impact of temperature and unwanted impurities on slow compression of ice.

For slowly compressed hexagonal ice pressure-induced amorphisation to high-density amorphous ice (HDA) takes place below and at 130 K, but polymorphic transformation to ice IX takes place at 140-170 K. Stable ice II only forms above 170 K. Ice IX impurities trigger ice IX growth even at 120 K.

Advances in the study of supercooled water.

In this review, we report recent progress in the field of supercooled water. Due to its uniqueness, water presents numerous anomalies with respect to most simple liquids, showing polyamorphism both in the liquid and in the glassy state. We first describe the thermodynamic scenarios hypothesized for the supercooled region and in particular among them the liquid-liquid critical point scenario that has so far received more experimental evidence.

Near-Infrared Spectra of High-Density Crystalline HO Ices II, IV, V, VI, IX, and XII.

High-pressure ice polymorphs are important for our understanding of hydrogen bonding and exist in the interior of the earth and icy moons. Nonetheless, spectroscopic information about them is scarce, where no information about their optical properties in the near-infrared (NIR) region is available at all. We here report NIR spectra of six ice polymorphs differing in terms of their density and O-atom topology, namely, ices II, IV, V, VI, IX, and XII, in comparison with the known spectra of ice I.

Open questions on the structures of crystalline water ices.

Water can form a vast number of topological frameworks owing to its hydrogen-bonding ability, with 19 different forms of ice experimentally confirmed at present. Here, the authors comment on open questions and possible future discoveries, covering negative to ultrahigh pressures.

High-density amorphous ice: nucleation of nanosized low-density amorphous ice.

The pressure dependence of the crystallization temperature of different forms of expanded high-density amorphous ice (eHDA) was scrutinized. Crystallization at pressures 0.05-0.