C. Wei et al., RECIPROCITY THEOREMS AND PSEUDOELECTRIC FIELDS FOR AB-INITIO FORCE CALCULATIONS, Physical review. B, Condensed matter, 55(23), 1997, pp. 15356-15359
We present a method for constructing a pseudoelectric field at each pa
int in space, which gives the force on a classical ion due to its loca
l or nonlocal pseudopotential interaction with a quantum electronic sy
stem. Our derivation extends a classical reciprocity theorem used by H
ellmann and Feynman for purely Coulombic interactions to a family of g
eneralized electron-ion potentials, which are useful for efficient ele
ctronic structure studies. The method is computationally efficient and
it should be particularly useful for structural relaxation and molecu
lar dynamics studies of complex systems.