Dear Ruibin ibrav(1) means you are using a simple cubic in your calculations and when you use a large celldm(1)=30 (Bohr) it is clear that your vectors are:
V1=30(1,0,0) V2=30(0,1,0) V3=30(0,0,1) think over !!! you have a very spacious box and a molecule inside it. so your molecule feel alone. For more details about periodic systems and crystals please read some pages of an elementary solid state book and the PW manual. I hope it helps. Best Wishes, m ---------------------------------------- Masoud Nahali SUT masoud.nahali at gmail.com alum.sharif.edu/~m_nahali On Sat, Nov 3, 2012 at 10:44 AM, Ruibin Wrote: > > Thank you! In QE, we use supercell to isolate a molecule, right? I don't > understand the differences between isolated and periodic systems in QE. > Anyway, other parameters are as follows: > &system > ibrav = 1, celldm(1) =30.0, nat= 14, ntyp= 2, > ecutwfc = 30.0, ecutrho = 300.0 > / > &electrons > diagonalization='david' > electron_maxstep = 50, > conv_thr = 1.0e-6 > mixing_beta = 0.1 > ATOMIC_SPECIES > C 12.011 C.blyp-van_ak.UPF > H 1.008 H.blyp-van_ak.UPF > K_POINTS Gamma > > How can I change them? > > -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20121103/c3db49af/attachment.html
