Vikas Varshney wrote: > Dear All, > > My final motivation is to simulate adsorption of several small > molecules on Al2O3 slab. The strategy I am undertaking (and hence I > have few questions) is below. Please correct me if I am wrong at any > stage of my calculation. > > I want to get the ground state of the Al2O3 slab. In this regard, I > got the unit cell of Al2O3 which is trigonal ( Space group R-3c, point > group D3d, 30 atoms) . This is not the primitive unit cell (which is > rhombhohedral and contain 10 atoms). The reason is to eventually > simulate 0 0 1 surface. It seems that the structure consist of 2 basis > atoms. The rest are defined by different symmetry operations for the > point group of Al2O3. > > Is is possible to make use of symmetry operations and run the > calculation on unit cell of Al2O3 by specifying only two basis atoms > and then run slab calculation with 30 atoms? Or should I just create > a 30 atom unit cell with vacuum along Z direction in a slab geometry > and relax it? I am not clear about your question much. Anyway, I do the simulation of adsorption on the slab by form a supercell that stores the substrate + vacuum + adsorbate atoms. You can see in previous archives to understand how to form a supercell.
Best, Linh > Best Regards, > Vikas > > > ------------------------------------------------------------------------ > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > -- ----------------------------------------------------- Nguyen Ngoc Linh, PhD Student c/o: SISSA & CNR-INFM Democritos, via Beirut 2-4, 34014 Trieste (Italy) email: nnlinh at sissa.it phone: +39 04 03787 319 skype: ngoclinh84phys ----------------------------------------------------- "The physics is theoretical but the fun is real"