CN molecule collisions with H+ at a wide range of astrophysical energies

TL;DR

This study provides detailed quantum-mechanical calculations of CN molecule collisions with protons across astrophysical energies, offering new cross sections and rate coefficients relevant for early Universe cosmology and CMB studies.

Contribution

It introduces precise quantum-mechanical cross sections and rate coefficients for CN-H+ collisions, improving upon previous approximate semiclassical models.

Findings

New excitation/de-excitation cross sections calculated

Thermal rate coefficients provided for a wide energy range

Results compared with previous approximate models

Abstract

We analyze the quantum-mechanical rotational excitation/de-excitation spectrum and cross sections of CN molecules during low and high-energy collisions with protons, H+. The problem is of significant importance in astrophysics of the early Universe, specifically connected with the problems of cosmic microwave background (CMB) radiation. A quantum-mechanical close-coupling method is applied in this work. The cyanide molecule (CN) is treated as a rigid rotor, i.e. the distance between the carbon and nitrogen atoms is fixed at an average equilibrium value. The new results of the excitation/de-excitation cross-sections and corresponding thermal rate coefficients are compared with the results of few previous calculations performed on the basis of few approximate semiclassical frameworks. The interaction potential between CN and H+ is taken in the following form: proton induced polarization potential + proton-dipole potential + proton-quadrupole potential.