[gmx-users] adding an external body force

[Michele Pellegrino]

Hi,


I was wondering how to apply an external forcing term to one group; looking at the 2020 documentation I found:


"

accelerate group
On each atom in an "accelerate group" an acceleration a_g is imposed. This is equivalent to an external force.

"


However I would argue it is not equivalent at all: the contibution of an external body force would add an acceleration term, not impose it, right?

To make a more concrete example, what if I want to simulate gravity by setting 'accelerate' to some value? Would I obtain free-falling or would gravity be added on top of the force field from atomic intercations?


Thanks for your attention.


Michele