Efficient method for quantum calculations of molecule - molecule scattering properties in a magnetic field

TL;DR

This paper introduces an efficient computational method for calculating molecule-molecule scattering properties in magnetic fields, enabling larger basis sets and more accurate simulations, with applications to ultracold molecule cooling.

Contribution

The authors develop a new angular momentum basis approach that significantly improves the efficiency of quantum scattering calculations in magnetic fields.

Findings

Supports feasibility of evaporative cooling of 15NH molecules

Enables larger basis sets for more accurate calculations

Validates previous predictions on molecule cooling in magnetic traps

Abstract

We show that the cross sections for molecule - molecule collisions in the presence of an external field can be computed efficiently using a total angular momentum basis, defined either in the body-fixed frame or in the space-fixed coordinate system. This method allows for computations with much larger basis sets than previously possible. We present calculations for 15NH - 15NH collisions in a magnetic field. Our results support the conclusion of the previous study that the evaporative cooling of rotationally ground 15NH molecules in a magnetic trap has a prospect of success.