We present evidence that the S = 1 Haldane-Shastry model has a gap in
the energy spectrum, extending to the case of a model with long-range
interactions results previously obtained by Haldane and, numerically,
by other authors for the case of short-range interactions. We studied
the groundstate and first excited state using a modified Lanczos algor
ithm and obtained the low temperature behavior diagonalizing exactly s
mall chains. The correlation functions decay exponentially with distan
ce and the low-T susceptibility decays exponentially to zero. The gap
is larger than for the Heisenberg model and the correlation functions
decay faster indicating a smaller correlation length.