Quantum theory of chemical reactions in the presence of electromagnetic fields

TL;DR

This paper develops a quantum scattering theory to analyze how external electric fields influence chemical reactions involving atoms and diatomic molecules, showing that fields can enhance reaction probabilities and alter resonances at low temperatures.

Contribution

The authors introduce a rigorous quantum scattering framework incorporating external electric fields, enabling detailed analysis of field effects on low-temperature chemical reactions.

Findings

Electric fields can increase reaction probabilities.

External fields modify reactive scattering resonances.

Reactions of polar molecules can be controlled below 1 K.

Abstract

We present a theory for rigorous quantum scattering calculations of probabilities for chemical reactions of atoms with diatomic molecules in the presence of an external electric field. The approach is based on the fully uncoupled basis set representation of the total wave function in the space-fixed coordinate frame, the Fock-Delves hyperspherical coordinates and adiabatic partitioning of the total Hamiltonian of the reactive system. The adiabatic channel wave functions are expanded in basis sets of hyperangular functions corresponding to different reaction arrangements and the interactions with external fields are included in each chemical arrangement separately. We apply the theory to examine the effects of electric fields on the chemical reactions of LiF molecules with H atoms and HF molecules with Li atoms at low temperatures and show that electric fields may enhance the probability of chemical reactions and modify reactive scattering resonances by coupling the rotational states of the reactants. Our preliminary results suggest that chemical reactions of polar molecules at temperatures below 1 K can be selectively manipulated with dc electric fields and microwave laser radiation.