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The University of Southampton
Chemistry

Why don’t we find more polymorphs? Seminar

Time:
16:00
Date:
6 November 2013
Venue:
Building 27, Room 2001 Chemistry Highfield Southampton SO17 1BJ

For more information regarding this seminar, please email Dr Simon Coles at S.J.Coles@soton.ac.uk .

Event details

The Molecular Assembly Function & Structure and Computational Systems Chemistry sections will be co-hosting the following seminar

Crystal Structure Prediction (CSP) studies successfully generate the thermodynamically favourable crystal packings of a molecule. However there are often more such structures than polymorphs found in interdisciplinary studies performed within the project “Control and Prediction of the Organic Solid State”. Analysis of the types of structures on the crystal energy landscape suggests that there are a variety of reasons for this. Improved modelling of thermodynamics could eliminate many structures as unstable relative to other phases or show that they are manifest within the dynamic or static disorder in the observed phases. However, other low energy unobserved structures raise the question as to whether they could be found as metastable polymorphs, or within other solid phases, given the right experiment and characterisation technique. Hence, calculating the crystal energy landscape can help rationalise experimental observations, and set limits to the range of possible polymorphs. However, the examples in this lecture illustrate why we will over-predict polymorphism until we have a quantitative understanding of the kinetic factors that determine the outcome of the huge range of possible crystallisation experiments.

Speaker information

Prof Sarah (Sally) Price, Department of Chemistry, University College London. .

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