The CP2K project : input section EWALD

Section EWALD

Index of all sections. This section is located at __ROOT__%FORCE_EVAL%DFT%POISSON%EWALD.

Ewald parameters controlling electrostatic only for CLASSICAL MM. This section can not be repeated and can be optional.

This section cites following references: [Ewald1921] [DARDEN1993] [ESSMANN1995] [Toukmaji1996] [Laino2008]

Subsections

Section keywords

Keyword descriptions

EWALD_TYPE
EWALD_TYPE {EWALD|SPME|PME|NONE}
The type of ewald you want to perform. NONE standard real-space coulomb potential is computed together with the non-bonded contributions. EWALD is the standard non-fft based ewald. SPME is the smooth particle mesh using beta-Euler splines (recommended). PME is the particle mesh using fft interpolation.
This optional keyword expects a keyword. Default value: EWALD
valid keywords: NONE, EWALD, PME, SPME
This keyword cites following references: [Ewald1921] [ESSMANN1995] [DARDEN1993]
EWALD_ACCURACY
EWALD_ACCURACY {real}
Expected accuracy in the Ewald sum. This number affects only the calculation of the cutoff for the real-space term of the ewald summation (EWALD|PME|SPME). This keyword has no effect on the reciprocal space term (which can be tuned indipendently).
This optional keyword expects a real. Default unit: [hartree], default value: 9.9999999999999995E-07 hartree
ALPHA
alpha .30
alpha parameter associated with Ewald (EWALD|PME|SPME). Recommended is alpha = 3.5 / r_cut.
This optional keyword expects a real. Default unit: [angstrom^-1], default value: 3.4999999999999998E-01 angstrom^-1
GMAX
gmax 25 25 25
number of grid points (SPME and EWALD). If a single number is specified,the same number of points is used for all three directions on the grid.If three numbers are given, each direction can have a different number of points.The number of points needs to be FFTable (which depends on the library used) and odd for EWALD.The optimal number depends e.g. on alpha and the size of the cell. 1 point per Angstrom is common.
This optional keyword expects a list of integers
NS_MAX
ns_max 11
number of grid points on small mesh (PME only), should be odd.
This optional keyword expects an integer. Default value: 11
O_SPLINE
o_spline 6
order of the beta-Euler spline (SPME only)
This optional keyword expects an integer. Default value: 6
EPSILON
epsilon 1e-6
tolerance of gaussians for fft interpolation (PME only)
This optional keyword expects a real. Default value: 9.9999999999999995E-07


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