The most important change in XD2024 concerns the initialisation program XDINI.

This now automatically recognises and handles the site symmetry restrictions for atoms in special positions. It also provides a more useful local coordinate system and local pseudo-symmetry for atoms in general positions. See the XDINI section in the XD manual for a full list of the modifications. The WinXD GUI has some minor modifications, but the remaining XD modules are essentially identical to those in XD2016.

The features of XD2016 include:

• Calulation of new properties in XDPROP, including reduced density gradient (NCI), Density Overlap Regions Indicator (DORI) and Single Exponential Decay Detector (SEDD).
• Calculation of intermolecular interactions. Electrostatic interactions are calculated from the experimental multipole moments using the highly accurate EPMM method which eliminates the serious approximations of the non-overlapping charge density inherent in the Buckingham expression. Non-electrostatic interactions are evaluated through atom-atom potential curves which can be custom-selected. Lattice energy is also computed based on direct space summation. These features represent an updated and corrected version of XDINTER.
• New routines to compute the molecular electrostatic potential, field and field gradients, based on the separated integration of Slater-type density functions (to be published). All the integrated properties available for rho(r) are available for the electrostatic potential as well.
• Scattering factors and wave functions for atoms up to Z = 109 (including relativistic effects) are now available in the databank.
• Direct interface to existing graphic programs (such as MOLEKEL, MOLDEN and GaussView03) and crystallographic programs (such as PLATON and ORTEP). Visualisation of atomic graphs and interatomic surfaces using WinXD GUI
• The thermal probability density function can be visualized, including anharmonic components as represented in the Gram-Charlier formalism
• Integration of atomic basins available for both the molecule in the crystal and the molecule extracted from the crystal.
• Local and basin-integrated Source Function at any point in space.
• Dynamic memory allocation in XDPROP, TOPXD, XDFOUR. Future versions will have full dynamic allocation in all programs, with no arbitary limitations.