Full-dimensional quantum dynamics of SO(X³Σ^-) in collision with H₂

A six-dimensional (6D) potential energy surface (PES) for the SO(X -HSO(X³Σ^-)-H₂ system is computed using high-level electronic structure theory and fit using a hybrid invariant polynomial method. Full-dimensional quantum close-coupling scattering calculations have been carried out using this potential for rotational and, for the first time, vibrational quenching transitions of SO induced by H₂. State-to-state cross sections and rate coefficients of SO are reported for rotational transitions from rotational levels j₁ = 0–10 in the ground vibrational state neglecting fine-structure. Some selected state-to-state rotational rate coefficients are compared with previous theoretical results obtained using a rigid-rotor approximation. For vibrational quenching, state-to-state and total cross sections and rate coefficients were calculated for the transitions in SO(v₁=1,j₁) + H₂(v₂=0,j₂) → SO(v₁ ^′=0,j₁ ^′) + H₂(v₂ ^′=0,j₂ ^′) collisions with j₁ = 0–5. Cross sections for collision energies in the range 1 to 3000 cm⁻¹ and rate coefficients in the temperature range of 5–600 K are obtained for both para-H₂ (j₂ = 0) and ortho-H₂ (j₂ = 1) collision partners. The application of the results to astrophysics is discussed.