Section VELOCITY_SOFTENING

• A method to initialize the velocities along low-curvature directions in order to favors MD trajectories to cross rapidly over small energy barriers into neighboring basins. In each iteration the forces are calculated at a point y, which is slightly displaced from the current positions x in the direction of the original velocities v. The velocities are then updated with the force component F_t, which is perpendicular to N. N = v / |v|; y = x + delta * N; F_t = F(y) - 〈 F(y) | N 〉 * N; v' = v + alpha * F_t

• Section path: CP2K_INPUT / MOTION / MD / VELOCITY_SOFTENING

• This section cannot be repeated.

• Subsections

  • none

• Keywords

  • ALPHA
  • DELTA
  • STEPS

• Keyword descriptions

  ALPHA
  	ALPHA {Real}
  	Mixing factor used for updating velocities.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.50000000E-001

  DELTA
  	DELTA {Real}
  	Displacement used to obtain y.
  	This keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.00000000E-001

  STEPS
  	STEPS {Integer}
  	Number of softening iterations performed. Typical values are around 40 steps.
  	This keyword cannot be repeated and it expects precisely one integer.
  	Default value: 0