Laser Spectroscopy of Nil: New Electronic States and Hyperfine Structure

Abstract

Two new electronic transition systems of NiI namely: the [14.0] - X and the [15.7] - X transitions were observed and analyzed using laser vaporization/reaction supersonic free jet expansion and high resolution laser induced fluorescence spectroscopy. In addition, the (v, 0) bands with v = 6 - 10 of the previously identified [14.6] - X transition were found to be perturbed by the [15.7] state. All observed spectra show partially resolved hyperfine structure. Hyperfine width of rotational lines decreases rapidly as J increases suggested that the hyperfine structure for the [14.0] , the [14.6] and the [15.7] states conform to the Hund’s case a coupling scheme. The interaction between the [14.6] and the [15.7] states is evident in the progressive increase in hyperfine width in rotational lines of the [14.6] - X transition as the vibrational quantum number increases. Deperturbation procedures were successfully applied to analyze the interaction between these two states. Accurate molecular and hyperfine constants for the [14.0] , the [14.6] and the [15.7] states were obtained and interpreted. Intermission