A simple theoretical model of an ideal surface can be generated from the cif file, provided a single crystal XRD structure is available. Obviously, you must check for the electroneutrality of the block you generate. Such a surface can be generated directly with Mercury (CCDC). Although this method neglects the morphological features of a real surface, the chemicals absorbed on it, structural defects, and so forth, it can represent a model to verify the possibility of interaction with different compounds. I recently exploited this method in J. Coll. Int. Sci. 2015, 448, 320-330, where the ideal surface of calcite was modeled to investigate the interactions with oxalic acid derivatives.

Hope this helps. Regards, M.

There are many programs and, as Massimiliano mentioned already, Mercury is often used but there are also other programs out there like Crystal Maker which I like:

http://crystalmaker.com/crystalmaker/what-is/

It has a lot of more features than the simple visualization of surfaces so it might be a bit to complex for this purpose. 

Another program I used for that earlier is AutoCAD where I assembled the crystal by copying the unit cell in all 3 dimensions and then I cut out the surfaces I needed. Its tedious work but you understand every step to get to the surface so later on you never forget how its constructed and where is it in the crystal. You can also make movies of the surfaces with a molecule on top once you have everything set up. I hope you get a little broader idea of what is out there. Good luck and ask here if you need help with the programs.

Mr. Barman,

By DIAMOND. It is available at:

http://www.crystalimpact.com/diamond/

I wonder what do you need? Do you simply need a software depicture more than a unit cell - then softwares like PowderCell mentioned above will deliver what do you need - or do you want to simulate the surface relaxation of a bulk material? Then non of these software packages work since they assume a perfect crystal. One can of course simulate an ideal arrangement of atoms and then uses Lennard-Jones potentials (or comparable) to calculate the resulting relaxed arrangement.  This is very valuable to investigate the effect of nanoparticles on the diffraction signal since there the surface is quite big in comparison to the volume of the crystal. 

Thanks Nolze. 

Yup, I want to simulate the surface relaxation of a bulk material. I can do this relaxation using VASP package. But i was just wondering how to make input POSCAR file for surface.

I guess, the easiest way is to use the translation symmetry of the crystal lattice, i.e. generate all atoms of a unit cell. These are all positions with relative atomic coordinates which are between 0

Dear Chanchal,

                                yes, there are many "commercial " softwares that can be used to  generate the surface structures of the crystal forms,  starting from the corresponding bulk structure. My research group tested many of these softwares since the eighties. Unfortunately, all of these softwares failed when the crystal structure is complex, especially when  polarity intervenes  and surface reconstruction is needed . Moreover, a crystal face can show more than one surface profile: in this case the best profile has to be selected in order to calculate either the surface or the attachment energy of the face.

A very nice theoretical method (  the Periodic Bond Chain method, made by Hartman and Perdok 60 years ago) can help to solve your problem, starting from the bulk structure, by applying suitable potential functions to describe the crystal field or using ab initio calculation. In any case, the surface profiles  of complex structures can be obtained by this method using (before calculation) the Hartman-Perdok way along with the best of the human resources (the reasoning)...

We obtained very nice and realistic results about the crystal morphology ( at equilibrium and after growth) on different and complex substances. I'm sending you some examples; we can discuss about this kind of working, if you are interested in, of course.

Thanks for your attention. All the best !

Dino 

@ D. Aquilano: the papers look very interesting and quite convincing. Could you say some words about well-known limitations (from your point of view)? We had a discussion somewhere else and I used the argument that e.g. calcite forms hundreds of different habits which you certainly cannot derive from this assumption, or can you? Thanks in advance, Gert

Dear Gert,

                            the papers I sent to Chanchal concern the theoretical morphologies of crystals calculated with respect to the vacuum ( and, approximately, with respect to its pure vapour). This is the first and necessary step (of course) for predicting any crystal morphology. Secondly, it is necessary considering the interaction of the crystal surfaces with the solvent (if any); eventual 2D epitaxy can be considered as well, in order to investigate peculiar adsorption of impurities.

Calcite (but not only calcite) shows thousands of morphologies... and my research group has been  the first to show not only the original equilibrium shape of the crystal but also the influence of 2D epitaxy of Li2CO3 on the growth shape of calcite. Further we showed the habit change of NaCl in the presence of formamide  (und so weiter...)

Thanks for your patience...

Dino

Dear Dino, your calculations look really fantastic. Congratulation!

Gert

Dear Chanchal,

I designed WinXMorph (Windows application), which reads in coordinates from a cif file, then uses the Bravais-Friedel, Donnay-Harker  model to simulate a morphology if the faces of the crystal are not already included in the cif:

http://cad4.cpac.washington.edu/WinXMorphHome/WinXMorph.htm

my program is free, by the way. In addition, it lets you export the morphology in cif syntax format which you can add to your cif file. Many additional features include treatment of twinning and you can add images to the surfaces if you want to create a realistic looking handpiece.

Hope, that helps.

     Werner