First principle study of crystal growth morphology: An application to crystalline urea

The growth morphology and the effects of surface reconstruction/relaxation of the habit faces on the crystal morphology of urea crystal are investigated from first principle using the Hartman-Perdok approach. A procedure has been developed to find out surface termination when a slab of d(hkl) thickness is created having {hkl} orientation. Slice energy of different habit faces have been computed and the attachment energy was calculated. The crystal growth morphology of the urea crystal has been drawn on the basis of computed attachment energies of different habit faces. The calculated crystal growth morphology depends on the functional employed for computing the attachment energies. The relaxed morphology obtained on the basis of attachment energy using Hartree-Fock method and B3PW density functional theory give a fairly good agreement with the as grown morphology from vapour phase while morphology computed using B3LYP functional underestimated {111}facet and predicted the appearances of {101} face. Polar solvent effects on the growth morphology were discussed particularly in the context of different atomic environments of {111} and {-1-1-1} faces.