  Electron-phonon interaction in superconducting transition metals (Ta, Mo, W)
is investigated by the method of point-contact spectroscopy. The spectra
obtained are compared with model densities of the phonon states $F(\omega)$
computed from experiments on neutron scattering, and with the tunnel
electron-phonon interaction function $g(\omega)$ for Ta. Close agreement
between the appropriate spectra is obtained for Ta and Mo, while a significant
discrepancy is observed for W, which is the appearance of a blurred maximum
instead of the two expected separated peaks on the point-contact spectra. The
absolute intensities of a number of point-contact spectra $G(eV)$ and
electron-phonon coupling constants $\lambda$ are calculated. For all three
metals the values obtained turned out to be considerably below those expected.
The possible reasons for this disagreement are discussed.
