Converged quantum-mechanical calculations of electronic-to-vibrational, rotational energy transfer probabilities in a system with a conical intersection

We present quantum-mechanical transition probabilities for the process Na(3p²P) + H₂(v₀ = 0, j₀ = 0,2) → Na(3s²S) + H₂(v′, j′) with zero total angular momentum where v₀, j₀, v′, and j′are initial and final vibrational and rotational quantum numbers. These calculations involve two coupled potential energy surfaces at a total energy of 2.431 eV, and the excited state has energetically accesible geometric configurations with HH internuclear distances 2.7 times larger than the H₂ equilibrium internuclear distance - which makes converged quantum-mechanical calculations very difficult. Covergence is demonstrated by obtaining the same results using two entirely different methods - R matrix propagation and the outgoing wave variational principle.