Abstract
The magnetophonon effect has been observed in the longitudinal and transverse magnetoresistance and the Hall voltage of n-InP under warm-electron conditions. Two distinct processes of electron energy relaxation are identified from the resonant structure: the first involves emission of a Gamma point LO phonon accompanied by the capture of the warm electron at an impurity site; the second corresponds to inter-Landau-level transitions by emission of a pair of TA phonons near the X point of the Brillouin zone. Three other extrema in the magnetoresistance are tentatively ascribed to resonant impact ionization of neutral donors.