Doppler-limited spectroscopy of the A3Π1 ← X1Σ+ system of ICl in the 0.8 μm region using a Ti:sapphire ring laser

► Spectroscopic constants of I35Cl and I37Cl belonging to the v = 0-7 and v = 0-6 in the A state are determined. ► Dunham expansion parameters in the X state are also determined. ► We demonstrate calculation of Dunham coefficients with Born-Oppenheimer approximation breakdown correction terms in the A-state.