List of Figures

• A schematic illustration of all-electron (solid lines) and pseudoelectron (dashed lines) potentials and their corresponding wavefunctions. The radius at which all-electron and pseudoelectron values match is . Source [22].
• A schematic illustration of a supercell geometry for a molecule. The boundaries of the supercell are depicted by dashed lines.
• Graph demonstrating the effect of the charged molecule corrections on the convergence of the energy of an molecule with supercell side length.
• A computer-generated image of the structure of thymine. (C=Grey, O=Red, N=Blue, H=Yellow)
• The atomic structure of thymine.
• A computer generated representation of the acetylcholine molecule. (C=Grey, O=Red, N=Blue, H=Yellow)
• The chemical structure of acetylcholine defining dihedral angles D1 through D4.
• A schematic diagram defining the planes relating to the constraints on the dihedral angles D2 and D3.
• A schematic diagram defining the vectors relating to the correction of dihedral angle D2.
• Results of static calculations. The point corresponding to the conformation of the acetylcholine chloride crystal is marked as a `+'.
• Results of relaxed calculations.
• Plot of energy difference between static and relaxed calculations.
• The calculated minimum energy conformation of acetylcholine showing electron density isosurface.
• The overall structure of .
• Schematic diagram of cytochrome P450 monooxygenase reaction with substrate RH and product ROH.
• The orientation of the haem moiety, CYS357 residue and 2-phenyl imidazole molecule in bound state. (C=Grey, O=Red, Fe=Orange, S=Yellow, N=Blue, H not shown)