Quantum Rovibrational dynamics of CS in collision with H$_2$*

Carbon monosulfide has been widely observed in a variety interstellar regions. An accurate prediction of its abundance requires collisional rate coefficients with ambient gases. Available collisional rate coefficients are limited to rigid-rotor calculations for a small range of rotational transitions in the vibrational ground state. In this work, we report the first six-dimensional (6D) PES for the CS-H$_2$ system. The PES was computed using high-level electronic structure theory and fitted using invariant polynomial method. Quantum scattering calculations were performed for rotational and rovibrational transitions of CS induced by H$_2$. Cross sections for rotational transitions from $j_1$=0-5 are compared with the results obtained within a rigid-rotor model. For rovibrational transitions, state-to-state and total quenching cross sections and rate coefficients were calculated for the vibrational quenching in CS($v_1=1, j_1$)+H$_2$($v_2=0, j_2$) $\rightarrow$ CS($v_1^{\prime}=0, j_1^{\prime}$)+H$_2$($v_2^{\prime}=0, j_2^{\prime}$) collisions, $j_1$=0-5. Cross sections for collision energies in the range 1 to 5000 cm$^{-1}$ and rate coefficients ranging from 5 to 1000 K are presented for both para-H$_2$ ($j_2$=0) and ortho-H$_2$ ($j_2$=1) collision partners.