The lowest energy states of van der Waals trimers of identical spinless bos
ons with one and two units of total angular momentum are examined. Paramete
rs corresponding to He-4 and para-H-2 are treated and the relation of the r
esults to level orderings for the rotation of rigid symmetric molecules is
discussed. The 2(+) rotational state of the para-H-2 trimer is bound by 3 K
relative to the dimer, while the rotational states of He-4(3), if any, hav
e binding energies of less than 1 mK relative to He-4(2). (C) 1999 American
Institute of Physics. [S0021-9606(99)01005-3].