An interaction-asymptotic region decomposition method for general state-to-state reactive scatterings

Area of Science:

• Quantum chemistry
• Chemical reaction dynamics
• Computational physics

Background:

• State-to-state reactive scattering calculations using the quantum wave packet method face challenges in finding optimal coordinates for both reactants and products.
• A consistent coordinate system is crucial for accurate modeling of chemical reaction pathways.

Purpose of the Study:

• To introduce and validate the Interaction-Asymptotic Region Decomposition (IARD) method for solving the coordinate problem in quantum reactive scattering.
• To enhance the efficiency and accuracy of quantum wave packet calculations for chemical reactions.

Main Methods:

• The Interaction-Asymptotic Region Decomposition (IARD) method employs locally optimal coordinate systems (hyperspherical and Jacobi coordinates) for different regions of the reaction.
• The method allows for extended grid boxes in the Jacobi coordinate R, accommodating large distances in both reactant and product arrangements.

Main Results:

• The IARD method enables efficient and accurate calculations with significantly larger grid sizes.
• Demonstrated effectiveness for the H + HD reaction (a simple direct reaction) and the F + HD reaction (involving resonances and slow translational energy products).

Conclusions:

• The IARD method effectively addresses the coordinate problem in quantum reactive scattering.
• It provides a robust and efficient approach for studying complex chemical reactions, including those with resonances and requiring long absorbing potentials.