Dilute nitride Films of GaAsN with high nitrogen homogeneity were grown by using the chemical beam epitaxy technique. This allowed us to investigate the electronic structure of the nitrogen-induced localized level (E-N) in GaAsN by photoreflectance measurements. We found that the E-N value decreased as the nitrogen content increased. Consideration of the energy levels of isolated nitrogen (N-x); pairs of nitrogen atoms (NNi) where i = 1, 2, and so On in order of increasing pair separation; and nitrogen clusters may help explain the changes in the estimated EN value. (C) 2013 Elsevier B.V. All rights reserved.