Section BEND

• Specifies the bend potential of the MM system.

• Section path: CP2K_INPUT / FORCE_EVAL / MM / FORCEFIELD / BEND

• This section can be repeated.

• Subsections

  • UB

• Keywords

  • ATOMS
  • CB
  • K
  • KBS12
  • KBS32
  • KIND
  • KSS
  • LEGENDRE
  • R012
  • R032
  • THETA0

• Keyword descriptions

  ATOMS
  	ATOMS {Word} {Word} {Word}
  	Defines the atomic kinds involved in the bend.
  	This keyword cannot be repeated and it expects precisely 3 words.

  CB
  	CB {Real}
  	Defines the the cubic force constant of the bend
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [rad^-1]

  K
  	K {Real}
  	Defines the force constant of the potential
  	This keyword cannot be repeated and it expects precisely one real.
  	Default unit: [rad^-2*hartree]

  KBS12
  	KBS12 {Real}
  	Mixed bend stretch parameter
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [rad^-1*bohr^-1*hartree]

  KBS32
  	KBS32 {Real}
  	Mixed bend stretch parameter
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [rad^-1*bohr^-1*hartree]

  KIND
  	KIND {Keyword}
  	Define the kind of bend potential
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: CHARMM
  	List of valid keywords: AMBER Functional Form (CHARMM|AMBER): K*(THETA-THETA0)^2 CHARMM Functional Form (CHARMM|AMBER): K*(THETA-THETA0)^2 CUBIC Functional Form (CUBIC): K*(THETA-THETA0)**2*(1+CB*(THETA-THETA0)) G87 Functional Form (HARMONIC|G87): 1/2*K*(THETA-THETA0)^2 G96 Functional Form (G96): 1/2*K*(COS(THETA)-THETA0)^2 HARMONIC Functional Form (HARMONIC|G87): 1/2*K*(THETA-THETA0)^2 LEGENDRE Functional Form (LEGENDRE): sum_{i=0}^N c_i*P_i(COS(THETA)) MIXED_BEND_STRETCH Functional Form (MIXED_BEND_STRETCH): K*(THETA-THETA0)**2*(1+CB*(THETA-THETA0))+ KSS*(R12-R012)*(R32-R032)+KBS12*(R12-R012)*(THETA-THETA0)+KBS32*(R32-R032)*(THETA-THETA0) MM3 Functional Form (MM3): 1/2*K*(THETA-THETA0)**2*(1-0.014*(THETA-THETA0)+5.6E-5*(THETA-THETA0)**2 -7.0E-7*(THETA-THETA0)**3+9.0E-10*(THETA-THETA0)**4)+KBS12*(R12-R012)*(THETA-THETA0)+ KBS32*(R32-R032)*(THETA-THETA0)

  KSS
  	KSS {Real}
  	Mixed bend stretch parameter
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [bohr^-2*hartree]

  LEGENDRE
  	LEGENDRE {Real} ...
  	Specifies the coefficients for the legendre expansion of the bending potential.'THETA0' and 'K' are not used, but need to be specified.Use an arbitrary value.
  	This keyword cannot be repeated and it expects a list of reals.
  	Default value: 0.00000000E+000
  	Default unit: [hartree]

  R012
  	R012 {Real}
  	Mixed bend stretch parameter
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [bohr]

  R032
  	R032 {Real}
  	Mixed bend stretch parameter
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+000
  	Default unit: [bohr]

  THETA0
  	THETA0 {Real}
  	Defines the equilibrium angle.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default unit: [rad]