Intra- and Intermolecular Interactions in and between Water Molecules in Calcium Sulfate Dihydrate

Abstract

A study of the infrared spectra of varyingly deuterated thin films of gypsum has afforded information on the relative importance of intra- and intermolecular interactions in determining the stretching bands of water in the spectrum. This study has indicated that the internal forces in water are different for water in gypsum than they are for water in the vapor. It is further indicated that the water molecule in gypsum is much like the average molecule expected to exist in the liquid state.

OD Stretching Vibrations in Deuterated Potassium Ferrocyanide Trihydrate

“…The same samples were used to study the OH fundamentals of HOD molecules. A negligible resolving of the bands due to intramolecular coupling was found, as was predicted in [7]. This justified the choice of DKFCT for the present investigations.…”

“…Using the isotope dilution technique [7] we were able to determine the uncoupled OD frequencies and to make some conclusions about the magnitude of the intra-and intermolecular interactions in this type of crystals. To our knowledge up to now this method has been applied only in infra-red experiments.…”

Observing non-classical crystallisation processes in gypsum via infrared attenuated total reflectance spectroscopy

“…[1][2][3] In addition, the intra-and intermolecular interactions between water molecules and gypsum have been investigated. 4,5 Compared to other non-soluble sulfates such as barite, water indeed plays a crucial role during the crystallisation process, as reported by Jones et al 6 Consequently, in the present study D 2 O was applied as an isotope marker for tracing the pathways of crystallisation in molecular detail. While it is anticipated that its molecular behaviour is similar to water, D 2 O has a distinct infrared signature facilitating its spectral differentiation from H 2 O even in mixtures.…”

On the Use of Overtone and Combination Bands for the Analysis of the CaSO4—H2O System by Mid-Infrared Reflection Spectroscopy

“…29 Conversely, for gypsum it has been demonstrated 33 that stretching bands of water are strongly influenced by intermolecular coupling with a behavior similar to that of liquid water. Kling et al 34 assigned to the highest wavenumber bands (3494 and 3550 cm À1 ) a m 3 character; the band at 3405 cm À1 may involve coupling components of the m 1 type, while the lowest wavenumber band at 3240 cm À1 is given as the first overtone of the H-O-H bend (2m 2 ), enhanced by Fermi resonance. The fact that water groups of gypsum have a behavior similar to that of liquid water is also proved by the broad band at about 470 cm À1 (Fig.…”