Section QMMM

• Input for QM/MM calculations.

• Section path: CP2K_INPUT / FORCE_EVAL / QMMM

• This section cannot be repeated.

• This section cites the following references: [Laino2005] [Laino2006]

• Subsections

  • CELL
  • FORCEFIELD
  • FORCE_MIXING
  • IMAGE_CHARGE
  • INTERPOLATOR
  • LINK
  • MM_KIND
  • PERIODIC
  • PRINT
  • QM_KIND
  • WALLS

• Keywords

  • CENTER
  • CENTER_GRID
  • CENTER_TYPE
  • DELTA_CHARGE
  • EPS_MM_RSPACE
  • E_COUPL
  • INITIAL_TRANSLATION_VECTOR
  • MM_POTENTIAL_FILE_NAME
  • NOCOMPATIBILITY
  • PARALLEL_SCHEME
  • SPHERICAL_CUTOFF
  • USE_GEEP_LIB

• Keyword descriptions

  CENTER
  	CENTER {Keyword}
  	This keyword sets when the QM system is automatically centered. Default is EVERY_STEP.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: EVERY_STEP
  	List of valid keywords: EVERY_STEP Re-center every step NEVER Never center SETUP_ONLY Center at first step only

  CENTER_GRID
  	CENTER_GRID {Logical}
  	This keyword specifies whether the QM system is centered in units of the grid spacing.
  	This keyword cannot be repeated and it expects precisely one logical.
  	Default value: .FALSE.

  CENTER_TYPE
  	CENTER_TYPE {Keyword}
  	This keyword specifies how to do the QM system centering.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: MAX_MINUS_MIN
  	List of valid keywords: MAX_MINUS_MIN Center of box defined by maximum coordinate minus minimum coordinate PBC_AWARE_MAX_MINUS_MIN PBC-aware centering (useful for &QMMM&FORCE_MIXING)

  DELTA_CHARGE
  	DELTA_CHARGE {Integer}
  	Additional net charge relative to that specified in DFT section. Used automatically by force mixing
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 0

  EPS_MM_RSPACE
  	EPS_MM_RSPACE {Real}
  	Set the threshold for the collocation of the GEEP gaussian functions.this keyword affects only the GAUSS E_COUPLING.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-010

  E_COUPL
  	E_COUPL {Keyword}
  	Specifies the type of the QM - MM electrostatic coupling.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: NONE
  	List of valid keywords: COULOMB Using analytical 1/r potential (Coulomb) - not available for GPW/GAPW GAUSS Using fast gaussian expansion of the electrostatic potential (Erf(r/rc)/r) - not available for DFTB. NONE Mechanical coupling (i.e. classical point charge based) POINT_CHARGE Using quantum mechanics derived point charges interacting with MM charges S-WAVE Using fast gaussian expansion of the s-wave electrostatic potential
  	Alias names for this keyword: QMMM_COUPLING, ECOUPL

  INITIAL_TRANSLATION_VECTOR
  	INITIAL_TRANSLATION_VECTOR {Real} {Real} {Real}
  	This keyword specify the initial translation vector to be applied to the system.
  	This keyword cannot be repeated and it expects precisely 3 reals.
  	Default values: 0.00000000E+000 0.00000000E+000 0.00000000E+000

  MM_POTENTIAL_FILE_NAME
  	MM_POTENTIAL_FILE_NAME {String}
  	Name of the file containing the potential expansion in gaussians. See the USE_GEEP_LIB keyword.
  	This keyword cannot be repeated and it expects precisely one string.
  	Default value: MM_POTENTIAL

  NOCOMPATIBILITY
  	NOCOMPATIBILITY {Logical}
  	This keyword disables the compatibility of QM/MM potential between CPMD and CP2K implementations. The compatibility is achieved using an MM potential of the form: Erf[x/rc]/x + (1/rc -2/(pi^1/2*rc))*Exp[-(x/rc)^2] .This keyword has effect only selecting GAUSS E_COUPLING type.
  	This keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  PARALLEL_SCHEME
  	PARALLEL_SCHEME {Keyword}
  	Chooses the parallel_scheme for the long range Potential
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: ATOM
  	List of valid keywords: ATOM parallelizes on atoms. grids replicated. Replication of the grids can be quite expensive memory wise if running on a system with limited memory per core. The grid option may be preferred in this case. GRID parallelizes on grid slices. atoms replicated.

  SPHERICAL_CUTOFF
  	SPHERICAL_CUTOFF {Real} {Real}
  	Set the spherical cutoff for the QMMM electrostatic interaction. This acts like a charge multiplicative factor dependent on cutoff. For MM atoms farther than the SPHERICAL_CUTOFF(1) their charge is zero. The switch is performed with a smooth function: 0.5*(1-TANH((r-[SPH_CUT(1)-20*SPH_CUT(2)])/(SPH_CUT(2)))). Two values are required: the first one is the distance cutoff. The second one controls the stiffness of the smoothing.
  	This keyword cannot be repeated and it expects precisely 2 reals.
  	Default values: -5.29177209E-001 0.00000000E+000
  	Default unit: [angstrom]

  USE_GEEP_LIB
  	USE_GEEP_LIB {Integer}
  	This keyword enables the use of the internal GEEP library to generate the gaussian expansion of the MM potential. Using this keyword there's no need to provide the MM_POTENTIAL_FILENAME. It expects a number from 2 to 15 (the number of gaussian functions to be used in the expansion.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 0