The simultaneous measurement of the photoelectron kinetic energy and angular distributions of NO were performed as a function of 410 nm laser intensities by femtosecond photoelectron imaging. The photoelectron kinetic energies are nearly independent of the laser intensities. The insensitivity of the photoelectron kinetic energy to the laser peak intensity suggests that peaks in the photoelectron spectra result from Freemen resonance, characteristic of the occurrence of real population on the intermediate states. The relative amplitudes of photoelectron peaks indicate that lower laser intensiti...
