H3(+) + H2 isotopic system at low temperatures: microcanonical model and experimental study

Area of Science:

• Physical Chemistry
• Chemical Physics
• Astrochemistry

Background:

• Hydrogen ion (H3+) and its isotopes are key molecules in interstellar chemistry.
• Understanding their reaction dynamics is crucial for modeling cold cosmic environments.

Purpose of the Study:

• To derive state-to-state thermal rate coefficients for H3+ + H2 isotopic reactions.
• To compare theoretical calculations with new experimental data.
• To provide data for astrochemical modeling.

Main Methods:

• Microcanonical approach using the Langevin model.
• Incorporation of conservation laws (mass, energy, angular momentum, nuclear spin).
• Consideration of full and partial nuclear scrambling (ergodic principle).

Main Results:

• Calculated rate coefficients are consistent with detailed balance and equilibrium constants.
• Experimental measurements of rate coefficients and equilibrium ratios were performed.
• Agreement between theoretical and experimental data is good, supporting theoretical predictions.

Conclusions:

• The study provides reliable theoretical rate coefficients for H3+ + H2 isotopic reactions.
• The findings support the use of these coefficients in astrochemical models of cold environments.
• Experimental data validates the theoretical approach and suggests potential changes in reaction mechanisms at higher temperatures.