Hi Chris, I thought it could be necessary, but it's been some days I've tried to subscribe and still have no answer, guess I'll have to wait a little longer then.
Thanks, Eric 2009/6/8 Christopher Rowan <chriskro...@gmail.com> > Hi Eric, > You must sign up for a user account on the SIESTA website to access > the pseudopotentials: this took a day or two for me. Then, once you > log in, on your user menu on the left you will see an option for > pseudos and bases. > Regards, > Chris > > 2009/6/8 Eric Perim <eric.pe...@gmail.com>: > > Thanks for the helpful tutorial. But where is this Siesta pseudopotential > > database you mention on it? > > > > Regards, > > Eric > > > > 2009/6/4 Zhong-Li Liu <zl.liu.c...@gmail.com> > >> > >> Dear Andrei, > >> Thank you for your kind reply, and I shall have some tests > >> according your suggestion. > >> > >> Best regards, > >> > >> Zhongli > >> > >> On 04/06/2009, apost...@uni-osnabrueck.de <apost...@uni-osnabrueck.de> > >> wrote: > >> >> Dear Andrei, > >> >> You said in your SIESTA-tuto that the frozen phonon calculations > >> >> usually > >> >> proceed after CG relaxation. > >> > > >> > Dear Zhongli, > >> > this is not obligatory, techniclly speaking, but any book on phonons > >> > tells you how they are introduced from Taylor expansion arond > >> > the equilibrium. So, this equilibrium first has to be found. > >> > If your system does not have internal coordiates you don't have > >> > to worry (say, for pure NaCl you can calculate phonons right away > >> > for any lattice constant without a need to relax), but if the internal > >> > cordinates are present (as say in wurtzite or rutile) - yes, > >> > the relaxation in principle should be done first. > >> > Oterwise, you have a chance to get imaginary modes > >> > with eigenector pointing towards the relaxed > >> > geometry, where the system would be able to lower its energy. > >> > > >> >> Is that means we should > >> >> first set "MD.TypeOfRun CG" to relax > >> > > >> > yes > >> > > >> >> and then change it to "MD.TypeOfRun FC" > >> >> with "UseSaveData T" > >> > > >> > yes > >> > > >> >> and "MD. UseSaveXV T" to calculate the force constants? > >> > > >> > No, in fact I suggested to copy the relaxed coordinates > >> > into the .fdf file and then proceed phonons with > >> > MD. UseSaveXV F > >> > But it is just a suggestion. > >> > > >> > Best regards > >> > > >> > Andrei > >> > > >> > >> > >> -- > >> PhD. student of IAMP, Sichuan University, China > >> E-mail: zl.liu.c...@gmail.com > > > > > > > > -- > > ========================================== > > Eric Perim Martins > > Universidade Estadual de Campinas - UNICAMP > > Instituto de Física Gleb Wataghin - IFGW > > Grupo de Sólidos Orgânicos e Novos Materiais - GSONM > > Departamento de Física Aplicada (DFA) - Sala 19 > > Campinas - São Paulo - Brasil > > CEP 13083-970 > > Telefone: (19)3521-0289 - Ramal 10289 > > MSN: pe...@nextwave.com.br > > ========================================== > > > -- ========================================== Eric Perim Martins Universidade Estadual de Campinas - UNICAMP Instituto de Física Gleb Wataghin - IFGW Grupo de Sólidos Orgânicos e Novos Materiais - GSONM Departamento de Física Aplicada (DFA) - Sala 19 Campinas - São Paulo - Brasil CEP 13083-970 Telefone: (19)3521-0289 - Ramal 10289 MSN: pe...@nextwave.com.br ==========================================
