Section UB

• Specifies the Urey-Bradley potential between the external atoms defining the angle

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

• This section cannot be repeated.

• Subsections

  • none

• Keywords

  • CS
  • K
  • KIND
  • R0

• Keyword descriptions

  CS
  	CS {Real}
  	Defines the cubic stretch term.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+00
  	Default unit: [bohr^-1]

  K
  	K {Real} ...
  	Defines the force constant of the potential. For MORSE potentials 2 numbers are expected. For QUARTIC potentials 3 numbers are expected.
  	This keyword cannot be repeated and it expects a list of reals.
  	Default unit: [internal_cp2k]

  KIND
  	KIND {Keyword}
  	Define the kind of Urey-Bradleypotential.
  	This keyword cannot be repeated and it expects precisely one keyword.
  	Default value: CHARMM
  	List of valid keywords: AMBER Functional Form (CHARMM|AMBER): K*(R-R0)^2 CHARMM Functional Form (CHARMM|AMBER): K*(R-R0)^2 CUBIC Functional Form (CUBIC): K*(R-R0)^2*(1+cs*(R-R0)+7/12*(cs^2*(R-R0)^2)) FUES Functional Form (FUES): 1/2*K*R0^2*(1+R0/R*(R0/R-2)) G87 Functional Form (HARMONIC|G87): 1/2*K*(R-R0)^2 G96 Functional Form (G96): 1/4*K*(R-R0)^2 HARMONIC Functional Form (HARMONIC|G87): 1/2*K*(R-R0)^2 MORSE Functional Form (MORSE): K1*[(1-exp(-K2*(R-R0)))^2-1]) QUARTIC Functional Form (QUARTIC): (1/2*K1+[1/3*K2+1/4*K3*|R-R0|]*|R-R0|)(R-R0)^2

  R0
  	R0 {Real}
  	Defines the equilibrium distance.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default unit: [bohr]