  We describe a robust and efficient chain-of-states method for computing
Minimum Energy Paths~(MEPs) associated to barrier-crossing events in
poly-atomic systems. The path is parametrized in terms of a continuous variable
$t \in [0,1]$ that plays the role of time. In contrast to previous
chain-of-states algorithms such as the Nudged Elastic Band or String methods,
where the positions of the states in the chain are taken as variational
parameters in the search for the MEP, our strategy is to formulate the problem
in terms of the second derivatives of the coordinates with respect to $t$, {\em
i.e.\/} the state {\em accelerations\/}. We show this to result in a very
transparent and efficient method for determining the MEP. We describe the
application of the method in a series of test cases, including two
low-dimensional problems and the Stone-Wales transformation in $\mbox{C}_{60}$.
