Susceptibility behavior of CuGeO3: Comparison between experiment and the quantum transfer-matrix approach

Thermodynamical properties of the one-dimensional S = 1/2 Heisenberg model with dimerized nearest and uniform next-nearest neighbor interactions are s tudied by the numerically exact quantum transfer-matrix method and the resu lts are applied to CuGeO3. The Suzuki-Trotter formula is used to obtain a c lassical system with spin sigma = 3/2 and effective interactions between ne arest neighbors only. The magnetic susceptibility curve is calculated and c ompared with experimental results in-a wide temperature range, revealing th e presence of frustration in the model proposed for CuGeO3. Temperature dep endence of the dimerization parameter below the spin-Peierls transition poi nt is also estimated. [S0163-1829(99)12941-2].