Recent neutron and Raman spectroscopic studies of squaric acid, a low-dimensional hydrogenbonded material

Squaric acid is a layered crystalline material with squaric molecules bonded by O-H...O-bonds, and showing a structural transition at 1000C. Recently Raman studies and incoherent neutron work have confirmed the earlier indication of local order being retained into the high-temperature phase, but new evidence from coherent neutron work points to a one-dimensional-like rather than a two-dimensional correlation above Tsub(c). The analysis of the data may point to a soliton-like type of excitations. (Auth.)