[en] A microscopic theory of the lattice dynamics of transition metals with high superconducting transition temperatures, especially vanadium and niobium, has been developed, based on the transition metal model potential method, in which the effects of s-d hybridisation is incorporated through an 1 = 2 model potential well depth of the resonance form. The theory shows that not only the general qualitative features but also the occurrence of soft modes in the phonon spectra of vanadium and niobium can be understood in the framework of the model potential methods; in particular s-d hybridisation contributes significantly to the occurrence of the soft modes through the local-field corrections to the free-electron screening function. (author)