On Wednesday, September 16, 2015 08:46:32 AM Naiwrit Karmodak wrote: > This is a 3,3 nanotube. I have also tried with 6,6 nanotube and the problem > is same. Both david and cg option for diagonalization is not giving any way > to optimized geometry. Please suggest a solution for this.
Dear Naiwrit, changing the type of diagonalization (cg or david) can affect the convergence of a single scf step, but the structure optimization will not change. If your structure breaks down it is because it is not stable, at least with the functional you are using. Visualizing your input with xcrysden I can see that all your carbon atoms are stuck together, which means that your input is wrong. My guess is that you wanted to specify the atoms positions as fractions of the crystall lattice vectors, in this case you have to use the "crystal" keyword: ATOMIC_POSITIONS crystal C 0.0863 0.1169 0.0443 C 0.9137 0.8831 0.132 .. Also note that specifying a k-point shift along the x and y directions is not correct, because you want wavefunctions which are periodic over the unit cell in those directions. I.e. use K_POINTS automatic 1 1 10 0 0 1 Finally, please disregards the advice from Bahadir, especially the one about smearing, as reducing smearing will not necessarily make convergence easier. HTH, kind regards -- Dr. Lorenzo Paulatto IdR @ IMPMC -- CNRS & Université Paris 6 +33 (0)1 44 275 084 / skype: paulatz http://www.impmc.upmc.fr/~paulatto/ 23-24/4é16 Boîte courrier 115 4 place Jussieu 75252 Paris Cédex 05 _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
