Full-Dimensional Quantum Dynamics of SiO in Collision with H₂

Abstract

We report the first full-dimensional potential energy surface (PES) and quantum mechanical close-coupling calculations for scattering of SiO due to H 2 . The fulldimensional interaction potential surface was computed using the explicitly correlated coupled-cluster (CCSD(T)-F12b) method and fitted using an invariant polynomial approach. Pure rotational quenching cross sections from initial states v 1 = 0, j 1 =1-5 of SiO in collision with H 2 are calculated for collision energies between 1.0 and 5000 cm −1 . State-to-state rotational rate coefficients are calculated at temperatures between 1 arXiv:1802.04702v1 [physics.chem-ph] 25 Jan 2018 5 and 1000 K. The rotational rate coefficients of SiO with para-H 2 are compared with previous approximate results which were obtained using SiO-He PESs or scaled from SiO-He rate coefficients. Rovibrational state-to-state and total quenching cross sections and rate coefficients for initially excited SiO(v 1 = 1, j 1 =0 and 1) in collisions with para-H 2 (v 2 = 0, j 2 = 0) and ortho-H 2 (v 2 = 0, j 2 = 1) were also obtained. The application of the current collisional rate coefficients to astrophysics is briefly discussed.

Evidence of Nonrigidity Effects in the Description of Low-Energy Anisotropic Molecular Collisions of Hydrogen Molecules with Excited Metastable Helium Atoms

“… 28 , 29 Lately, the larger complexes involving other atoms have been considered. The systems that are of interest to the astrochemical community, such as H 2 + CO, 16 , 30 , 31 H 2 + CN, 32 H 2 + SiO, 33 H 2 + CS, 34 H 2 + HCl, 35 and H 2 + SO, 36 have been investigated within the full-dimensional methods. For a broad list of references of these studies, see the recent review article of ref ( 18 ) and the book of ref ( 37 ).…”

“…Until recently, the full dimensional calculations for the van der Waals complexes containing two diatomic molecules have been limited to the simplest case, i.e., H 2 + H 2 . , Lately, the larger complexes involving other atoms have been considered. The systems that are of interest to the astrochemical community, such as H 2 + CO, ,, H 2 + CN, H 2 + SiO, H 2 + CS, H 2 + HCl, and H 2 + SO, have been investigated within the full-dimensional methods. For a broad list of references of these studies, see the recent review article of ref and the book of ref .…”

Controlling rotational quenching rates in cold molecular collisions

“…Scattering calculations for collisions of HD with H 2 were performed in full-dimensionality using a modified version of the TwoBC code 31 . This methodology has been applied to many other similar systems 19,[32][33][34][35] , and is outlined in detail elsewhere 30,36,37 . Here we briefly review the methodology in order to define notation.…”

Unraveling the Stereodynamics of Cold Controlled HD−H2 Collisions

“…Scattering calculations for collisions of HD with H 2 were performed in full-dimensionality using a modified version of the TwoBC code [35]. The methodology is well established and outlined in detail [29,31,36], and has been applied to other similar systems [37][38][39][40]. Here we briefly review the methodology in order to define notation.…”