On the relation between electronic structure and molecular dynamics

A formalism is developed for relating dynamic observables of collision processes to the electronic structure of the colliding species. Expressions are derived for functional derivatives of dynamic observables with respect to the full electronic wavefunction for the case of indistinguishable collision partners as well as for nonidentical partners. For wavefunctions described by orbitals, the formalism is extended to relate dynamic observables to electronic orbitals and orbital coefficients. The formalism is illustrated with the simple example of H + D and H + H elastic scattering cross sections at energies between 0.5 and 5.0 eV. Regions of the wavefunction which have particularly strong influence on the cross sections are identified by the functional derivatives. The manner in which the dynamics enters into the sensitivity is discussed. Particle indistinguishability is seen to influence the sensitivity of the collision to electronic structure.