The quantum transfer-matrix method (QTM) has been applied to study the fini
te-temperature static properties of the spin S=1 antiferromagnetic Heisenbe
rg chains and a ring with an alternating spin. The high-resolution QTM simu
lation data are obtained and some theoretical approaches are numerically ve
rified. Microscopic parameters of a number of real compounds are found from
the fitting procedures. (C) 1999 Elsevier Science B.V. All rights reserved
.