Dynamical spin correlation function S-zz(Q, w) with Q smaller than pi (m) o
ver bar ((m) over bar being magnetization) is derived exactly for the spin
chain with the 1/r(2) interaction in magnetic field. It is found that only
two spinons and one antispinon contribute to S-zz(Q, w) in the thermodynami
c limit. In deriving the result we use the solution of the Sutherland model
with internal symmetry in the strong coupling limit. Our theory keeps the
full symmetry of the model in contrast to the previous one which is based o
n mapping onto the single-component Sutherland model. (C) 2000 Elsevier Sci
ence B.V. All rights reserved.