Full-dimensional quantum rovibrational scattering of NaCl with H₂

Molecular collisional rate coefficients are required to predict the abundance of molecular gas

not in local thermodynamic equilibrium in the interstellar medium.

NaCl has been widely observed in a variety of interstellar regions and its

collisional rate coefficients with the dominant collision partner H2

are of astrophysical importance.

In this work, we present a full-dimensional quantum study of rovibrationally

inelastic scattering of NaCl with H₂ using

a six-dimensional potential energy surface constructed

with high-level ab initio calculations and an invariant polynomial fitting.

The scattering calculations were carried out for both rotational and rovibrational

transitions of NaCl induced by para- and ortho-H₂.

Cross sections for rotational transitions from j₁=0-30 of NaCl in the

ground vibrational state were computed for collision energies ranging from 1 to

5000 cm^-1. For rovibrational transitions,

state-to-state quenching cross sections were calculated for

the vibrational quenching in NaCl(v1=1, j1)+H2(v2=0, j2) --

NaCl(v'₁=0, j₁')+H2(v₂'=0, j₂') collisions,

with j1=0-1. State-to-state rate coefficients ranging from 5 to 1000 K are

presented for both para-H2 and ortho-H2) collision partners.