The CP2K project : input section UB

Section UB

Index of all sections. This section is located at __ROOT__%FORCE_EVAL%MM%FORCEFIELD%BEND%UB.

Specifies the Urey-Bradley potential between the external atoms defining the angle. This section can not be repeated and can not be optional.

Subsections

None

Section keywords

Keyword descriptions

KIND
KIND HARMONIC
Define the kind of Urey-Bradleypotential.
This optional keyword expects a keyword. Default value: CHARMM
valid keywords:
  • HARMONIC: Functional Form (HARMONIC|G87): 1/2*K*(R-R0)^2
  • CHARMM: Functional Form (CHARMM|AMBER): K*(R-R0)^2
  • AMBER: Functional Form (CHARMM|AMBER): K*(R-R0)^2
  • G87: Functional Form (HARMONIC|G87): 1/2*K*(R-R0)^2
  • G96: Functional Form (G96): 1/4*K*(R-R0)^2
  • QUARTIC: Functional Form (QUARTIC): (1/2*K1+[1/3*K2+1/4*K3*|R-R0|]*|R-R0|)(R-R0)^2
  • MORSE: Functional Form (Morse): K1*[(1-exp(-K2*(R-R0)))**2-1])
  • CUBIC: Functional Form (Cubic): K*(R-R0)**2*(1+cs*(R-R0)+7/12*(cs**2*(R-R0)**2))
K
K {real}
Defines the force constant of the potential. For QUARTIC potentials three numbers are expected.
This required keyword expects a list of reals. Default unit: [bohr^-2hartree].
CS
CS {real}
Defines the cubic stretch term.
This optional keyword expects a real. Default unit: [bohr^-1], default value: 0.0000000000000000E+00 bohr^-1
R0
R0 {real}
Defines the equilibrium distance.
This required keyword expects a real. Default unit: [bohr].


Back to the CP2K homepage or the latest version of this manual