Intra- and intermolecular effects in the Compton profile of water

Size, separation, structural order and mass density of molecules packing in water and ice

“…The d H of 1.0004 Å at unity density is within the measured values ranging from 0.970 to 1.001 Å21. The d OO values greater than the ideal value of 2.6950 Å at ρ = 1 (g·cm −3 ) correspond to the supersolid phase (low-density, LDP) that exists indeed272829 but only presents in the skins of water ice composed of molecules with fewer than four neighbors (Figure 4b)26.…”

“…The derived d H = 1.0004 Å at ρ = 1 is within the measurements ranging from 0.970 to 1.001 Å21. The d H shorter than 0.96 Å corresponds to the supersolid phase in regions of molecules having fewer than four coordination neighbors (CN)192026.…”

“…However, the structure order, the geometric symmetry, the size and the separation between molecules packing in water and ice (H 2 O) and their correlation remain yet highly disputed, independent issues despite decades-long intensive investigation. For instances, the separation between adjacent oxygen atoms (d OO ) was measured to vary from 2.70 to 3.00 Å891011121314151617181920 and the molecular size (the H-O bond length d H ) changes from 0.970 to 1.001 Å21. A H 2 O molecule demonstrates high instantaneous asymmetry with coordination numbers varying from two22 to four or even greater23.…”

Development and application of in situ/operando soft X-ray transmission cells to aqueous solutions and catalytic and electrochemical reactions

“…Several groups have measured O K-edge XAS [25,26,29,31,33,34] and hard X-ray Raman scattering [41] of liquid water at different temperatures and found that the pre-edge peak is sensitive to the temperature due to the local structural change of the HB network. The effect of temperature in liquid water has also been studied by neutron diffraction [98], nuclear magnetic resonance (NMR) [99], X-ray Compton scattering [100,101], and IR and Raman spectroscopy [102][103][104][105], and by MD simulations [105][106][107].…”

Beyond a single-determinantal description of the density matrix of periodic systems: Experimental versus theoretical Compton profiles of crystalline silicon

“…5,6 In recent years, this technique has been applied to the study of many "disordered" systems; [7][8][9][10][11] nevertheless, its main field of application still remains that of crystalline compounds, whose intrinsic anisotropy constitutes a source of additional information. [12][13][14][15][16][17] The importance of comparing accurate experimental and theoretical EMDs is clear from the above: this is precisely the aim of this study, which concerns the prototypical case of crystalline silicon.…”