Does the calculation of PMF depend on the path of the reaction coordinate?

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Dear GROMACS users,

I have a fundamental question about the Potential of Mean Force (PMF). Does this quantity a path-dependent value or not?

Let’s say we have two graphene sheets stacked on each other (see Figer below). Theoretically, does it make any difference if we choose reaction coordinates I or II to calculate the total PMF for a full separation of sheets? In other words, should we expect to see the same value for energy difference between state A and B regardless of our reaction coordinates?


Kind regards,

Ehsan

You’ll get different results as you’re illustrating two different movements; overall COM separation might be the same but there’s no real reason to think these will produce similar results. The PMF you calculate does depend on path; look into early work by Jarzynski for some related fundamental concepts.

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