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The freeenergy profile along a geometric parameter can be scanned by an approximate slowgrowth
approach [84].
In this method, the value of is linearly changed
from the value characteristic for the initial state (1) to that for
the final state (2) with a velocity of transformation
.
The resulting work needed to perform a transformation
can be computed as:

(6.31) 
In the limit of infinitesimally small , the work
corresponds to the freeenergy difference between the the final and initial state.
In the general case,
is the irreversible work related
to the free energy via Jarzynski's identity [74]:

(6.32) 
Note that calculation of the freeenergy via eq.(6.32) requires
averaging of the term
over many realizations of the
transformation.
Detailed description of the simulation protocol that employs Jarzynski's identity
can be found in Ref. [78].
Next: Performing the simulations
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