CCL:G: Mixed Gaussian and plane-wave DFT

[Herbert Fruchtl <herbert.fruchtl|,|st-andrews.ac.uk>]

 Sent to CCL by: Herbert Fruchtl [herbert.fruchtl/./st-andrews.ac.uk]
There are different "mixed basis" approaches for periodic
 systems. In the case
 of CP2K, you essentially use atom centred basis sets. The plane waves
 only come
 in as an expansion basis to make the calculation of integrals more
 efficient,
 but all orbitals are expressed in Gaussians following the LCAO
 approach. This
 means you have to put some thought into choosing the right basis set
 (not just a
 cut-off as in pure plane-wave codes). You also have BSSE, which is an
 error
 introduced by the fact that the basis set is geometry dependent.
This differs from muffin-tin based approaches (such as FLAPW), where
 you have
 atom centred basis functions to describe the atoms (or rather the area
 close to
 the nuclei, since there is no such thing as an atom...) and plane waves
 for the
 space in between.
 Hope this helps,
   Herbert
 On 26/07/18 04:42, Andrew Scott Rosen rosen:+:u.northwestern.edu wrote:
>  Sent to CCL by: "Andrew Scott Rosen" [rosen]*[u.northwestern.edu]
>  Dear compchem listserv,
>  Does anyone here have familiarity with the mixed Gaussian and plane-wave
>  (i.e. GPW) approach used in CP2K for periodic DFT? If so, what are the
>  limitations of the GPW method in CP2K compared to periodic DFT codes that
>  just use plane-waves, such as VASP? Are there any?
>  Andrew>
 --
 Herbert Fruchtl
 Senior Scientific Computing Officer
 School of Chemistry, School of Mathematics and Statistics
 University of St Andrews
 --
 The University of St Andrews is a charity registered in Scotland:
 No SC013532