On Fri, 09 Apr 2010 06:38:50 +0200, siva rama krishna <sivaramakrishnaj at gmail.com> wrote: > Similarly, can we arrest the Z-component of the centre of mass of a > molecule > ?
No, you cannot. pw.x does not have the concept of molecule at all. Furthermore, if you put the molecule on teh substrate and it just breaks, than the centre of mass would pretty much loose any meaning. This does not mean that it is impossible to implement, actually it should be quite easy; have a look at Module/constraints_module.f90. regards -- Lorenzo Paulatto *** Note: my affiliation has changed! please send future correspondence to: <Lorenzo.Paulatto at impmc.upmc.fr> *** post-doc @ IMPMC/UPMC - Universit? Paris 6 phone: +33 (0)1 44 27 74 89 www: http://www-int.impmc.upmc.fr/~paulatto/ previously: phd student @ SISSA & DEMOCRITOS (Trieste) phone: +39 040 3787 511 www: http://people.sissa.it/~paulatto/
