Quantum exchange effects in trimer ground states

Abstract
The ground state of molecular trimers is studied in three dimensions for these pair potential models: the square well, the exponential, the Yukawa, the Gaussian, and the Lennard‐Jones 12–6. Three spin cases are considered: three spin‐zero bosons and the spin‐ (1/2) and spin‐ (3/2) states of three spin‐ (1/2) fermions. Variational wavefunctions are constructed which satisfy the exchange symmetry requirements for these cases. Bounds are obtained for the threshold coupling constants at which self‐bound trimers occur. Consequences for possible self‐bound trimers of 3He are discussed.