A combined study, using reflection high energy electron diffraction (RHEED) and reflection anisotropy spectroscopy (RAS), has been carried out on clean (001)InP surfaces prepared in a solid-source molecular beam epitaxy (MBE) reactor. Experiments performed under non-growing (static) conditions show the existence of a number of surface reconstructions, including two distinctive (2 X 4) phases at higher substrate temperatures. As the temperature is decreased (2 X 1), (2 X 2) and c(4 x 4) reconstructions are found. The c(4 X 4) reconstruction, observed for the first time, has a significantly different RA signature than that found for GaAs, indicating that a different surface model is necessary in this case. The RHEED patterns and RA spectra recorded for the growing (dynamic) InP surface are similar to that of the static surface, with the RA-signal differences between the two being accountable by the effective change in the P-2 overpressure at the surface. Under conventional growth conditions, we have observed monolayer oscillations in the RA signal during the initial stages of InP epitaxy for the first time. (C) 1998 Elsevier Science B.V.