Deperturbation of the rotational spectrum of the d3Δ-a3П (7, 1) band of CS radical

► The spectral lines of CS were observed by laser absorption spectroscopy. ► New branches and lines were observed and identified. ► The anomalous lambda-doubling of the d3Δ1 (υ = 7) level was detected and discussed. ► The molecular constants including perturbation were determined accurately.