Visible light emission from atoms and ions sputtered on a polycrystalline Ti surface was observed under irradiation of 30 keV Ar3+ ions. A number of atomic lines of Ti I and II were observed in the wavelength of 250-850 nm. The intensity of Ti II emission increased 1.3-5.6 times by introducing oxygen molecules at a pressure of 5.8 x 10(-5) Pa, whereas that of Ti I decreased 0.5-0.8 times. Factors enhancing or reducing photon intensities were plotted as a function of energy of the corresponding electrons in the excited states for Ti atoms and Ti+ ions. (C) 2011 Elsevier B.V. All rights reserved.