[Tares]

a : a theory that physical matter is the only or fundamental reality and that all being and processes and phenomena can be explained as manifestations or results of matter

I'll go with definition "a", if we can consider "matter" to mean "matter/energy".

Is free will a manifestation or result of matter/energy?

[PatrickHenry]

Is free will a manifestation or result of matter/energy?

Only living beings have free will. As far as anyone knows, all aspects of living beings are manifestations of matter/energy. If free will is derived from something other than matter/energy, I don't know what that would be.