[CPMD-list] Size of cell for SURFACE/POLYMER ?

[jarek at elrond.chem.uni.wroc.pl]

Dear CPMD users,

I have a question related to the latest discussion on the 2D calculations
in CPMD. What is the required cell length in the "non-periodic dimensions"
for SURFACE, POLYMER or, while we are at it, ISOLATED MOLECULE? The
standard supercell approach would require the sufficiently large length
for decoupling of the periodic images, but what about the options listed
above? Should we include, say, 3 or 4 A of "free space" from the most
protruding atoms? If anyone has got either a theoretical explanation or
the empirical rule of thumb, I would be happy for hearing it.

And, of course, happy summer holidays to you all!

Jaroslaw Panek
Faculty of Chemistry, University of Wroclaw
ul. F. Joliot-Curie 14, 50-383 Wroclaw, Poland