Abstract: Angle-resolved supersonic molecular beam scattering techniques are used to examine the angular distributions of the products formed in thermal and UV laser-induced reactions of chlorine molecular beam with InP(100) surface. For the thermal reaction, the angular distributions of InCl_2~+, InCl~+, PCl~+, PCl_2~+ and P_4~+ products are slightly peaked towards the normal of the surface and vary as cos~(1.5)θ, θ being the detection angle from the surface normal. The effect of the normal components of the transla-tional energies of Cl_2 molecules is also observed at different angle of incidence. Under 355 nm pulsed laser irradiation, the time-of-flight (TOF) spectra of InCl~+ are measured as a function of the detection angle and Maxwellian characterized with the mean kinetic energy or translational temperature. The flux distributions are sharper than cosine law and can be fitted by an expression of F(θ)=a·cosθ+(1-a)cos~nθ, where a and n are adjustable parameters. The mean kinetic energy distribution of InCl molecules is strongly peaked around the surface normal and decreases with increasing the detection angle. These results imply that both thermal and nonthermal desorption mechanisms are important in the UV laser-induced reaction processes.