THE ab initio CALCULATION OF THE HELLMANN-FEYNMAN FORCE AND ITS APPLICATIONS IN THE STUDY ON THE CHEMICAL BOND I. THE THEOEY AND THE CALOULATION
Qs Du, Zr Peng · Acta Chimica Sinica · 1984
In the present investigation the theory and the formulae of the ab initio calculation of Hellmann-Feynman force are presented, the FORTRAN IV general program ABHF is made. On the basis of the works of others and the LOAO-MO theory, the formulae for analysis of the electronic force are proposed. The calculations of the H-F force obtained from the polycentral GTO basis set, which is given by us, and from the program ABHF are better than those obtained from the basis sets 4-31G and 6-31G, and from the Clementi's wave function of the molecule HF(16 STO). The net force acting on the nucleus F is 0.022575 a. u. and on the nucleus H is -0.057023 a. u. in our calculations. The results of the calculations of the energy, dipole moment and virial value are improved.