<DIV id=RTEContent>Dear all,</DIV> <DIV>the WIEN2k supercell method is still not obvious to me. StructGen gives </DIV> <DIV>all these options for lattice structures (P, F, H, e.t.c). How does one build a</DIV> <DIV> supercell starting from StructGen. The FAQ is not explicit on that, and I think a </DIV> <DIV>step-by-step example for supercell calculations would help those of us who </DIV> <DIV>are beginners and doing independent calculations.</DIV> <DIV> </DIV> <DIV>I posted a mail with regards to computing the total energy of </DIV> <DIV>isolated CO2 molecule. Someone suggested the supercell method. </DIV> <DIV>The truth is that I simply don't get how to build a supercell. </DIV> <DIV>The answer to the supercell FAQ does not elucidate on how to build supercells. </DIV> <DIV>So, I tried the FCC lattice method to computing Cohesive energies of </DIV> <DIV>atoms outlined in the FAQ ( note that I used the P option for the </DI!
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<DIV>lattice instead of F because of warnings in "x sgroup").</DIV> <DIV> </DIV> <DIV>A couple of other Questions concerning RMT and bond lengths:</DIV> <DIV> </DIV> <DIV>(1) Should I position O and C such the distance is close to </DIV> <DIV> the experimental C=O bondlength?</DIV> <DIV> </DIV> <DIV>(2) If I decide to implement point (1) above then I'm forced to choose the RMTs </DIV> <DIV> such that </DIV> <DIV> </DIV> <DIV> RMT(C) + RMT(O) less than or equal to C-O bond-length</DIV> <DIV>otherwise I get an error in the nn list.</DIV> <DIV> </DIV> <DIV>(3) These choices of RMT in point (2) are small so I have to decrease RKMAX and increase GMAX. Otherwise I get all manner of warning (especially RKMAX </DIV> <DIV>reduced because of NNTMAX). What is an appropriate RKMAX and GMAX in</DIV> <DIV> such a situation? </DIV>
<DIV> </DIV> <DIV> Can anyone suggest a nice, simple and smooth way to compute the energy </DIV> <DIV>of the isolated molecules. </DIV> <DIV> </DIV> <DIV>Thanks!</DIV> <DIV> </DIV> <DIV>J. Appleton</DIV> <DIV> </DIV>