Full-dimensional quantum dynamics of SO(X 3 Σ - ) in collision with H2

A six-dimensional (6D) potential energy surface (PES) for the SO(X -HSO(X 3 Σ - )-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 j 1  = 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( v 1 = 1 , j 1 ) + H2( v 2 = 0 , j 2 ) → SO( v 1 ′ = 0 , j 1 ′ ) + H2( v 2 ′ = 0 , j 2 ′ ) collisions with j 1  = 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 ( j 2  = 0) and ortho-H2 ( j 2  = 1) collision partners. The application of the results to astrophysics is discussed.