Section QMMM

• Input for QM/MM calculations.

• Section path: CP2K_INPUT / FORCE_EVAL / QMMM

• This section cannot be repeated and cannot be optional.

• 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

  • DELTA_CHARGE
  • EPS_MM_RSPACE
  • E_COUPL
  • INITIAL_TRANSLATION_VECTOR
  • MM_POTENTIAL_FILE_NAME
  • NOCENTER
  • NOCENTER0
  • NOCOMPATIBILITY
  • PARALLEL_SCHEME
  • SPHERICAL_CUTOFF
  • TYP_CENTER
  • USE_GEEP_LIB

• Keyword descriptions

  DELTA_CHARGE
  	DELTA_CHARGE Q
  	Additional net charge relative to that specified in DFT section. Used automatically by force mixing
  	This optional 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 optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-10

  E_COUPL
  	E_COUPL GAUSS
  	Specifies the type of the QM - MM electrostatic coupling.
  	This optional 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) NONE Mechanical coupling (i.e. classical point charge based) 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 optional keyword cannot be repeated and it expects precisely 3 reals.
  	Default values: 0.00000000E+00 0.00000000E+00 0.00000000E+00

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

  NOCENTER
  	NOCENTER LOGICAL
  	This keyword disables the automatic centering of the qm system every MD step.It centers the system only for the first step. Default .FALSE. (i.e. the QM system is centered every step)
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  NOCENTER0
  	NOCENTER LOGICAL
  	This keyword disables the automatic centering of the qm system every MD step even for the first step. Default .FALSE. (i.e. the QM system is centered every step)
  	This optional keyword cannot be repeated and it expects precisely one logical.
  	The lone keyword behaves as a switch to .TRUE.
  	Default value: .FALSE.

  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 optional 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 (ATOM|GRID)
  	Chooses the parallel_scheme for the long range Potential
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: ATOM
  	List of valid keywords: ATOM parallelizes on atoms. grids replicated. GRID parallelizes on grid slices. atoms replicated.

  SPHERICAL_CUTOFF
  	SPHERICAL_CUTOFF <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 optional keyword cannot be repeated and it expects precisely 2 reals.
  	Default values: -5.29177209E-01 0.00000000E+00
  	Default unit: [angstrom]

  TYP_CENTER
  	TYP_CENTER NONE
  	This keyword specifies how the QM system is centered with respect to the QM box during MD.
  	This optional keyword cannot be repeated and it expects precisely one keyword.
  	Default value: NONE
  	List of valid keywords: GRID centering is performed in units of the grid spacing NONE centering is performes continuously

  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 funtions to be used in the expansion.
  	This optional keyword cannot be repeated and it expects precisely one integer.
  	Default value: 0