The meaning of "KAPPA" in the "MOVINGRESTRAINT"

[Zhang Cheng]

I am using the command below to drag the "distance.contact-1" from 0.79 to 0.6

restraint: ...

        MOVINGRESTRAINT

        ARG=distance.contact-1

        AT0=0.79 STEP0=0      KAPPA0=0

        AT1=0.60 STEP1=3000   KAPPA1=10000

...

But only 0.65 was achieved in 3000 steps.

Then I increase the "KAPPA1" to 50000, and it achieves nearly 0.60 in 3000 steps.

So my understanding is, the "KAPPA1" indicates the amplitude of the external energy applied to the system, dragging the system to the desired value of a collective variable. But it is better to choose a "KAPPA" that is low but sufficient enough to achieve the target, so that we do not apply too much "unnatural" forces to the system. Is that correct?

Thank you!

Cheng