Exact triple-avoided-crossing resolution for three-body molecular systems

The hyperradial-adiabatic approach is used to study a region of localized triple-avoided crossing. A three-by-three orthogonal transformation involving a system of strongly coupled hyperradial Schrödinger equations is developed, leading to an exact coherent compensation of all peaks in the matrix elements of adiabatic corrections. In other words, the closure relation between adiabatic corrections matricesH+Q²=0, which formally holds for a complete basis set, is nicely saturated by three strongly interacting states. One may suggest this to be a property of the hyperradial-adiabatic basis.