In a one-electron transfer reaction
A + D ![[reversible arrow]](/img3/R_files/REVARR.gif)
A. - + D.+
the reorganization energy ![[lambda]](/img3/R_files/LAMBDA.gif)
is the energy required for all structural adjustments (in the reactants and in the surrounding solvent molecules) which are needed in order that A and D assume the configuration required for the transfer of the electron. See intrinsic barrier, Marcus equation.
