The relationship between the Hellmann-Feynman force and the derivative
s of the energy components with respect to a nuclear coordinate is pre
sented. The electrostatic force given by the electrostatic theorem is
found to consist of the derivatives of expectation values of the kinet
ic energy, one-electron energy, and two-electron energy operators. Con
sidering the difference between the derivative and gradient on a react
ion coordinate, it is found that the former is the preceding force at
the given reaction coordinate while the latter is composed of the prec
eding force and coupling terms. The zero-virial path (ZVP) is one of t
he reaction paths, where the ratio of the potential and kinetic energi
es maintains the value -2. On this path, since the ratios are constant
, the energy-component analysis was considered to be impossible. Howev
er, using the derivatives such an analysis was found to be possible. E
xamples are given by using vinylalcohol and singlet vinylcarbene.