Radiative transition probabilities and lifetimes for the band systems (1) 3Π–X 3Σ− and (2) 3Σ−–X 3Σ− of the isovalent molecules BeC, MgC, and CaC

Accurate potential energy curves, transition moments, spectroscopic constants, radiative transition probabilities, and lifetimes for the states X 3Σ−, (1) 3Π, and (2) 3Σ− of BeC, MgC, and CaC are reported using high level calculations. Diagonal transitions dominate for the (2) 3Σ− → X 3Σ− system, with band origins falling at 745, 648, and 770 nm, and an intensity ratio of 6,3,1, respectively for BeC, MgC, and CaC. Radiative lifetimes for v′=0 are equal to 0.48, 1.45, and 3.29 μs for the state (2) 3Σ−, and equal to 13.57, 10.44, and 9.62 μs for the state (1) 3Π for BeC, MgC, and CaC.