Research interests


First Principles Calculations on Iron and Iron alloys

Equation of state of hcp- and bcc-Fe and FeSi, the bcc-hcp phase transition, the magnetic moment of bcc-Fe, the elastic constants of bcc-Fe, the bcc-bct distortive phase transition and the phonon frequencies for bcc- and fcc-Fe [6];
hcp-Fe is the likely phase for a pure iron core on thermodynamic grounds [8, 14, 29];
Although bcc-Fe is mechanically destabilised by pressure, temperature may enable it to become mechanically stable at core conditions (stress tensors and position correlation functions) [34, 60]
Although thermodynamically less stable than hcp, bcc-Fe could be stabilised by light elements such as Si [27, 31];
elasticity of iron at high temperatures and pressures [51, 58, 67]
bcc transforms to the omega phase at low temperatures [60];
high pressure DOS of bcc- and hcp-Fe [22];
high pressure elastic constants and thermodynamic properties of hcp-Fe [37];    
theoretically derived seismic wave velocities for bcc- and hcp-Fe [22];
determine the viscosity of liquid iron and FeS [7, 17];
the curious 7-fold coordinated structure of FeSi possibly associated with s-p-d hybridisation [9];
equation of state of Fe3C and implications for carbon in the core [30];
high temperature elastic constants of Fe, FeSi, FeS and Birch's Law [51, 58, 67];
in situ viscosity and diffusion experiments [18, 21]
a new high pressure phase of FeSi [27, 31]
light elements in the core [27, 31, 51, 59, 62, 64, 68 ]
the effect of nickel on iron in the Earth's core and relevant end-members [46, 73]



 
Neutron diffraction experiments at ISIS

thermal expansion and crystal structure of FeSi [26];
thermal expansion and crystal structure of Fe3C [38];
thermoelastic properties of {Mg,Fe}O [61];
planetary ices (see below).
 

First Principles Calculations on the Melting Curve of Aluminium and Copper

The phonon dispersion and melting curve of aluminium from the free energies of both the solid and liquid via thermodynamic integration from suitable reference systems, with thermal averages calculated using ab-initio molecular dynamics [28].

The phonon dispersion and melting curve of copper using the coexistence approach with ab initio corrections to the classical reference system via thermodynamic integration [39].
Experimental copper melting curve [48]
 

Planetary Ices via ab initio calculations and neutron diffraction experiments with Dominic Fortes

NH3.H2O (AMH) and NH4OH [23]
NH3.2H2O (ADH) [32, 36, 53, 66]
NH3 [33]
Ice II [35, 43]
Epsomite [47]
MgSO4 [50]
Ammonium sulphate [52, 63]
Sulphuric acid hydrates [57]
mirabilite [65, 70]
 

Other Work

Classical molecular dynamics melting of MgO [4]   
the Grüneisen parameter [1, 15]
equation of state of magnesite [10]
diffusion in MgO [2]
RuSi [16]
post-perovskite ananlogues [71, 72]