Ab initio potential energy surfaces and nonadiabatic collision dynamics in H(+)+O(2) system

Area of Science:

• Theoretical Chemistry
• Quantum Dynamics
• Atomic and Molecular Collisions

Background:

• Understanding ion-molecule collisions is crucial for atmospheric chemistry and plasma physics.
• Previous studies lacked detailed quantum dynamics for the H(+) + O(2) system.

Purpose of the Study:

• To compute adiabatic potential energy surfaces and nonadiabatic coupling terms for the H(+) + O(2) collision system.
• To investigate vibrational elastic and inelastic excitations of O(2) and charge transfer processes.
• To compare theoretical findings with experimental data.

Main Methods:

• Multireference configuration interaction (MRCI) calculations with Dunning's correlation consistent polarized valence triple zeta (cc-pVTZ) basis set.
• Ab initio computation of quasidiabatic potential energy matrix and vibrational coupling matrix elements.
• Quantum dynamics simulations using the vibrational close-coupling rotational infinite-order sudden (VCC-IOS) framework.

Main Results:

• Accurate potential energy surfaces for five electronic states of (3)A" symmetry were obtained.
• Computed vibrational coupling matrix elements match experimental trends for O(2) inelastic vibrational excitations.
• Theoretical predictions for vibrational excitations and charge transfer show good agreement with experimental proton energy-loss spectra.

Conclusions:

• The study provides a robust theoretical framework for understanding H(+) + O(2) collisions.
• The results validate the accuracy of the employed computational methods against experimental observations.
• This work advances the understanding of energy transfer and reaction pathways in ion-molecule systems.