A¹Σ_u⁺-X¹Σ_g⁺ emission in Na₂ is observed following excitation ofB¹π_u by various lines of an argon ion laser. The excitation energy ofB¹π_u is collisionally transferred to the (2)¹Σ_g⁺ which then radiatively populates theA¹Σ_u⁺ state. The Na vapour is contained in a stainless steel crossed heat pipe with Ar buffer gas and temperature around 600°C. For all laser lines except 4579 Å, the coarse features ofA-X emission are independent of the laser wavelength. However, at high resolution the finer differences between different laser line excitation are explained. Variousv′-v″ transitions in this emission are identified. Computer simulation is presented to help explain some features of this emission.