Sir with your suggestions I have constrained two pentacene molecules stacked one above the other using flags. But it did not worked. so please provide me a detailed definition and syntax for using constraints.
I also have another doubt, I am constructing a metal-organic interface.I built an layered structure using matreial studio and the cartesian coordinates are taken using chemcraft. How should I input the coordinates in quantum espresso, whether cartesian or fractional and the also cell parameters of the specified layered structure. Thanks in advance. On 6/13/11, m.g.p.krishna at chem.leidenuniv.nl <m.g.p.krishna at chem.leidenuniv.nl> wrote: > Hi Yuva, > > If you look at the previous post, you can see a small example script, > where a CONSTRAINT card is used. Also to use CONSTRAINT card you > SHOULD use 'damp' rather than 'bfgs'. It is easy to use 'distance' > constraint. > > But I failed to fix the coordination number for selected atoms (using > 'atom_coord' and 'type_coord') as It described in the previous mail. > > Moreover some strange things are there, for example > from the previous input, it do a relaxation if you use: > > CONSTRAINTS > 1 0.5 > 'atom_coord' 5 1 3.5 0.5 > > > and you will get an ERROR message if you swap the atom index (VERY > STRANGE): ie. > > CONSTRAINTS > 1 0.5 > 'atom_coord' 1 5 3.5 0.5 > > So someone can help us to give a working/reliable example script on > 'atom_coord' and 'type_coord' constraints. It will be very useful, > since the default examples dont include this... > > otherwise I am going to do a Quantum-Espresso plugin for ASE/CamD just > for a reliable geometry optimization. :-( > > With best regards > > Krishna Mohan GP > Center for Superfunctional Materials > POSTECH > Sotuh Korea. > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum >
