Towards a full quantum mechanical treatment of atom-triatom inelastic collisions*

Despite computational methodologies designed to model atomic and molecular inelastic collisions being widely available nowadays, these are yet restricted to small systems such as atom--diatom and diatom--diatom within the time-independent quantum mechanical approach. Moreover, recent advances in AMO physics brought to attention physical conditions (i.e. ultracold collisions, light--assisted excited colliding partners, high atomic densities etc.) and heavy atomic/molecular species (often also charged) that are nearly numerically intractable. In particular, after steady advances in the early 90's, the atom--triatom case is yet lacking a full quantum mechanical approach. In this work we propose a time--independent formalism, based on a set of arrangement--fixed Jacobi coordinates, to model collisions and scattering of an atom by a triatomic target, accounting for all degrees of freedom. Numerical results are presented for the case study H$_{2}$O + H.