Reactor-scale simulation of metalorganic vapor phase epitaxy (MOVPE) by computational fluid dynamics is now widely attempted, but it is still difficult to predict group V composition precisely for InGaAsP. In this study, desorption of As and P from the surface of GaAs, InAs, GaP, InP, InGaAs and InGaP was measured around growth temperatures using in situ reflectance anisotropy (RA) spectroscopy. Time transient curves of RA were measured when group V supply was turned on/off and the rate constants of the desorption of As and P were measured assuming first-order kinetics. These data were incorporated into the simulation to obtain the composition of InGaAsP. The simulated distribution of group V composition showed better agreement with experimental data than the results using previous kinetic data. (c) 2008 Elsevier B.V. All rights reserved.