Calcite and related materials: growth and dissolution - Report of Workshop
4-5th January 2001
Department of Chemistry, University of Reading
About 41 people gathered in Reading in the first week of the New
Year to discuss the problems associated with growth and dissolution
of materials. Much, though not all, the work presented here was
associated with calcite. Phosphates, sulphates, clays and zeolites
also put in an appearance. A particularly valuable feature of the
meeting was the discussions between the modellers and experimentalists.
The two invited speakers (Brigid Heywood was also invited but was unable
to come at the last minute) illustrated this debate.
Susan Stipp
(Copenhagen) gave an extended review of the interactions of
calcite in water. She emphasised the fact that experimental surfaces, even
in high vacuum were
never free from water or organic material. Her work on dissolution shows
the variety of behaviour that occurs; how etch pits begin as rhombohedra,
exhibiting the geometry of the calcite surface. However, they quickly
produce rounded edges. On a larger scale, complex behaviour at terraces
and edges is seen. This is a challenge for modelling at both the atomistic
and the meso scale. Becker (Munster) presented work on dissolution; this time
on sulphates and showed the effect of the ionic strength of the solution on
dissolution behaviour. Several members of Brigid Heywood's group were present,
showing the complexities of calcite behaviour in the presence of organic
molecules and templates.
Randy Cygan
(Sandia) discussed the derivation of potential
models for carbonates and phosphates. Other presentations (Refson, Cora,
Stackhouse) illustrated the increasing use of local density calculations
in the field. Simulations using classical potentials were still well
represented. Steve Parker (Bath) discussed the dolomite problem (the mineral,
not the mountains). David Heyes showed how simulation can attack nano-scale
problems; surfactants around calcite particles.
The timeliness of the meeting was shown both by the number of participants
and by the extended discussions in the bar afterwards. It was agreed that
a network should be set up to help the participants (and others) to
exchange ideas and formulate new projects in what is clearly a rapidly
changing field.
Last modified 28 October 2002
