Four-body singlet potential-energy surface for reactions of calcium monofluoride

Abstract

A full six-dimensional Born-Oppenheimer singlet potential-energy surface is constructed for the reaction CaF $+$ CaF $\ensuremath{\rightarrow}\phantom{\rule{4pt}{0ex}}{\mathrm{CaF}}_{2} +$ Ca using a multireference configuration-interaction electronic structure calculation. The ab initio data thus calculated are interpolated by Gaussian process regression. The four-body potential-energy surface features one ${D}_{2h}$ global minimum and one ${C}_{s}$ local minimum, connected by a barrierless transition state that lends insight to the reaction mechanism. This surface is intended to be of use in understanding ultracold chemistry of CaF molecules.