Near-infrared Y2Σ+-X2Π transition of CuS

The near-infrared electronic transition of CuS has been observed for the first time. The spectrum of the Y2Σ+-X2Π transition, labeled by analogy with the CuO near infrared electronic transition, was recorded with the Fourier transform spectrometer associated with the McMath-Pierce Solar Telescope, Kitt Peak, Arizona. The excited CuS molecules were produced in a King-type carbon tube furnace operating at 1900 °C and at a total pressure of approximately 400 Torr. The electronic transition energy and vibrational constants for the Y2Σ+ state of 63Cu32S are presented.