Intertek ASG Computational Chemistry Group

Solid State Properties

Analysis of published crystal structures can be used to give a first indication of preferred molecular orientations, packing motifs and non-bonded interactions. Molecular modelling techniques can be applied to help understand chemical effects and behaviour at the molecular level. Using the most sophisticated software currently available, it is possible to start to predict how individual molecules might pack together and rank possible polymorphic forms based on their predicted energies.

To find out more on each of these areas, see below:

• Crystal Structure Analysis
• Modelling of Chemical Effects and Behaviour
• Polymorph Prediction

For information on experimental crystallography services see:

• Intertek Crystallography Capabilities

Crystal Structure Analysis

The number of published and archived crystal structures, obtained using both X-ray and neutron diffraction methods, is rapidly increasing. Crystal structure databases can be searched and mined to analyse molecular conformation and packing motifs. Using knowledge bases extracted from subsets of these databases, intermolecular interactions can be studied for a wide variety of interacting chemical groups.

Techniques applied for crystal structure analysis include:

• Analysis of molecule conformation
• Identification of packing motifs
• Study of types and preferred orientations of intermolecular interactions
• Simulation of X-ray powder diffraction patterns

Email ASGlab@intertek.com for more information

Modelling of Chemical Effects and Behaviour

Molecular modelling techniques such as molecular mechanics, molecular dynamics and ab initio methods can be used to help understand chemical effects and behavior at the molecular level. Molecules can be investigated in the gas phase, in solution, or in the solid state.

Techniques applied in this area include:

• Molecular geometry optimisation
• Molecular conformational analysis
• Chemical reaction analysis via energetics
• Charge distribution analysis
• Molecular dynamics simulations for studies of:
  • molecule - molecule interactions
• molecule - solvent interactions
• molecule - surface interactions

Email ASGlab@intertek.com for more information

Polymorph Prediction

Using some of the most sophisticated molecular modelling software currently available, it is possible to start to investigate and predict how individual molecules might pack together in the solid state. By generating a large number of possible packing motifs in many different space groups and then ranking each of these in terms of lattice energy, an indication of which polymorphic forms might be expected experimentally cn be obtained.

Polymorph prediction involves the following steps:

Email ASGlab@intertek.com for more information