Application of the Regional Density Functional Theory: The Chemical Potential Inequality in the HeH~+ System

摘要

The chemical potential inequality and the principle of maximum hardness along the reaction coordinate in the ion-atom reaction system He + H~+ -> HeH~+ are discussed in term of the regional density functional theory. The regional properties such as the regional transfer potentials #tau#_(P, Q), the regional excitation potentials #epsilon#_(P,Q), and the regional hardnesses #theta#_(P,Q) are calculated along the reaction coordinate using regional Hellmann-Feynman forces, and we prove numerically that the regional chemical potentials, #mu#_p and #mu#~(Q), are not necessarily equal to each other nor to the chemical potential #mu# of the whole system by means of the difference rule, #tau#_p - #tau#_Q = #mu#_p - #tau#_(Q), where P denotes an electron-acceptor region and Q denotes an electron-donor region. The electronic state is in the ground state along the reaction path and attains the maximum hardness at the nuclear equilibrium point where the reaction stops. The regional chemical potentials come close but are not equalized even at the nuclear equilibrium point.