By Onwuagba, Beniah Ndudim
Recent experildental and theoretical studies or the
electron-phonon intermtion in Group VB &band metals vanadium,
niobium an? tant~Jum which c r y s t d l i z e in the body - centered
cubic phase, a c ~ i : that their phonon spectra exhibit same soft
modes believed t o be due t o electronic band structure effects
and local field corrections. These metals have received
considerable att.ention because of t n e occurrence of these soft
modes; the high superconducting transition temperature
associeted with then! md their compounds such ae vanadium
+in (v3 ~n); and metal insulator transition in vanadium
trioxi.de {V3 0 3 ) md vanadium ni t r ide (vN),
The purpose ot t h i s thesis is to formulate in an
inhmmll-J consistent mmner the theory of the local field
corrections t o %he dynmical matrix for phonon dispersion
relation in these d-band metds and to exhibit the appa:-ent
cancellation be.t;yew,t. heee ooxect ions and repulsive shortrange
forces, This w i l l be done in the transition metal
model potential (T?4MP) approximation of O l i and Animalu
(1916) which w i l l enable I us .t. o invest igate t h e pos s ibi l i ty of
i-epresent ing the local field correction associated with r-d
interactions as an attractive short-range interatomic force