Rate constants for the H⁺ + H₂ reaction from 5 K to 3000 K with a statistical quantum method

Area of Science:

• Chemical Physics
• Quantum Mechanics
• Atomic and Molecular Collisions

Background:

• Proton-hydrogen molecule collisions are fundamental in astrophysics and plasma physics.
• Understanding state-to-state transitions is crucial for modeling interstellar medium and fusion environments.

Purpose of the Study:

• To investigate state-to-state transitions in H+ + H2 collisions.
• To calculate integral cross sections and rate constants for various rovibrational levels.
• To determine the cooling rate coefficient of H2 excited by protons.

Main Methods:

• Employs a statistical quantum method assuming a complex-forming nature of the reaction.
• Calculates integral cross sections for collision energies from 10^-5 eV to 2 eV.
• Determines rate constants for temperatures ranging from 5 K to 3000 K.

Main Results:

• Provides state-resolved integral cross sections for H2(v=0, j=0-12), H2(v=1, j=0-8), and H2(v=2, j=0-3).
• Calculated rate constants are compared with existing literature values.
• The cooling rate coefficient for proton-excited H2 is determined.

Conclusions:

• The statistical quantum method effectively models H+ + H2 state-to-state transitions.
• The study offers valuable data for astrophysical and plasma simulations.
• The calculated cooling rate coefficient provides a benchmark for future studies.