The emission spectroscopy of the C2Σ+-X2Π system of the CD radical

Abstract The emission spectrum of the 0 - 0 , 1 - 1 and 2 - 2 bands of the C 2 Σ + - X 2 Π system in the CD molecule have been obtained using a stainless steel hollow-cathode lamp with two anodes and filled with a mixture of He buffer gas and CD 4 . The emission from the discharge was observed with high accuracy dispersive optical spectroscopy using a plane-grating spectrograph and recorded by a photomultiplier tube. In total, 428 transition frequencies belonging to the three bands were precisely measured and rotationally analyzed. The current data were elaborated with the help of precise ro-vibrational and equilibrium ground state parameters reported by Zachwieja et al. (2012) from investigation of the A 2 Δ - X 2 Π transition. The spin-rotation interaction constants γ v and γ D , v of the C 2 Σ + , v = 0 , 1 , 2 levels were obtained for the first time. Moreover, the main equilibrium parameters of the third excited state were obtained as follows: T e = 31 , 825.944 ( 12 )  cm −1 , ω e = 2078.803 ( 27 )  cm −1 , ω e x e = 59.558 ( 12 )  cm −1 , B e = 7.86810 ( 23 )  cm −1 , α e = 0.25315 ( 58 )  cm −1 and γ e = - 0.01518 ( 28 )  cm −1 .