Comparative study of He-3, Ne-3, and Ar-3 using hyperspherical coordinates

We calculate the L=0 ground and excited state energies for the rare gas tri mers He-3, Ne-3, and Ar-3. An adiabatic representation is adopted to solve the nuclear Schrodinger equation, in which the Schrodinger equation in hype rangular coordinates is solved at a series of fixed hyper-radii using B spl ines. We compare results obtained in a strict adiabatic approximation with nonperturbative coupled-adiabatic-channel calculations. Structural properti es such as the pair and angle distributions are monitored as functions of t he hyper-radius. These structural studies pinpoint the locus of configurati onal changes that occur as the trimer fragments into a diatom plus an atom. Analysis of the angular channel functions and their associated radial comp onents permits an approximate classification of the vibrational spectrum. ( C) 2000 American Institute of Physics. [S0021-9606(00)00230-0].