Hi there, I am trying a very simple MD calculation (optical phonon mode of Silicon, similar to the original Car-Parinello paper). I am surprised that the total energy is not constant but oscillates with about 10% of the amplitude of the potential energy.
This oscillation is *independent* of the MD time step. Furthermore it did not change with the k-grid, the energy cutoff, the functional or the pseudopotentials. Attached is one of the input files that I used. Does anyone know what might cause this behavior? Greetings, Norbert -- GMX DSL: Internet-, Telefon- und Handy-Flat ab 19,99 EUR/mtl. Bis zu 150 EUR Startguthaben inklusive! http://portal.gmx.net/de/go/dsl -------------- next part -------------- A non-text attachment was scrubbed... Name: in.pwscf Type: application/octet-stream Size: 704 bytes Desc: not available Url : http://www.democritos.it/pipermail/pw_forum/attachments/20100624/02db3d98/attachment.obj
