Dear Prof. Garcia Many thanks for your response.
I looked up the MM.Potentials block but I couldn't figure out how to apply the harmonic potential to selected atoms. Any assistance would be appreciated. Thanks! Francisco On Mon, Nov 13, 2023 at 1:51 AM Alberto Garcia <[email protected]> wrote: > Hi Francisco, > > You could indeed modify the constr.f file to include what you need, but > first check the section of the manual entitled "Auxiliary Force Field". In > there you can find a discussion of the MM.Potentials block, in which you > can define the parameters of, among others, a harmonic potential. > > Best regards, > > Alberto > > > ----- El 11 de Noviembre de 2023, a las 09:13, Francisco Garcia < > [email protected]> escribió: > > Dear Users, > > The constraint subroutine takes the form: subroutine constr( cell, na, > isa, amass, xa, stress, fa, ntcon ). It doesn't contain information about > energy. > > Now I am using a harmonic potential with a stiff spring to constrain a > pair of atoms separated by a distance of r0. I should be able to pass the > constraint harmonic energy V=1/2 * k * (rij - r0)^2 to the subroutine to be > added to the total energy i.e., E + 1/2 * k * (rij - r0)^2 will be the > total energy. > > Which routines should I modify to allow the total energy to account for > the constraint energy? > > > > > -- > SIESTA is supported by the Spanish Research Agency (AEI) and by the > European H2020 MaX Centre of Excellence ( > https://urldefense.com/v3/__http://www.max-centre.eu/__;!!D9dNQwwGXtA!V_yhBOHCFFxdY5WMcg2Vv8Ymb5CUuYr4dpyQyrnB8zQRuVGasPatUDFCuulHsnFCbVfyyrstpp82eApPAg3lvMc$ > ) > > >
-- SIESTA is supported by the Spanish Research Agency (AEI) and by the European H2020 MaX Centre of Excellence (http://www.max-centre.eu/)
