Dr Maslen is recognized internationally for his contributions to high-resolution Xray diffraction imaging of the three-dimensional electron density distribution in crystals. His work has stressed the significance of the pro-molecule (the set of overlapping but undeformed atoms at their equilibrium positions) and the dominance of exchange in redistributing electron density. The evidence he has provided has permitted critical assessment of theoretical predictions of certain basic chemical and physical properties. His unified approach bears on the structural geometry, bonding energy and charge distribution in crystalline solids. More recently, he has shown how access to synchrotron X-radiation has enhanced the potential of his approach.
