[gmx-users] constant velocity pulling/Umbrella sampling

[raghav singh]

Hello Fellow Users,

I have a doubt about the mdp option in case of constant velocity pulling /
Umbrella pulling simulation.

pull            = umbrella
pull_geometry   = distance      ; simple distance increase
pull_dim        = N N Y
pull_start      = yes           ; define initial COM distance > 0
pull_ngroups    = 1
pull_group0     = Chain_B
pull_group1     = Chain_A**pull_rate1      = 0.01          ; 0.01 nm
per ps = 10 nm per ns
**pull_k1         = 1000          ; kJ mol^-1 nm^-2*

Pull_rate1 = velocity variable for CVP
Pull_k1    = is this option is for constant force pulling OR THIS IS SPRING
CONSTANT FOR THE VIRTUAL SPRING???

because i am trying to follow Justin's umbrella sampling tutorial and when
i remove this PULL_K1 option...then the COM Pull Energy ... does not change
and the ligand never get pulled away.??

guys Please help me out here.

Thank you in Advance.

cheers
Raghav