Amc. De Souza et Ca. Macedo, Magnetic behavior of the organic polymers m-polydiphenylcarbene by the Hubbard model, J MAGN MAGN, 226, 2001, pp. 2026-2027
Utilizing the Hubbard model, we studied the correlation among electrons of
the organic m-polydiphenylcarbene molecules. We discuss their thermodynamic
properties in the framework of grand canonical quantum Monte-Carlo simulat
ions. We present the temperature dependence of the internal energies, corre
lation functions and paramagnetic susceptibilities for the m-1, -2, -3 and
-4diphenylcarbene. Our results show an antiferromagnetic correlation at low
-temperatures. The gradual transition temperatures of states of paramagneti
c-antiferromagnetic correlation are similar for all the studied molecules.
This explains why the characteristic temperature of the decrease of the mul
tiplicity of spins (ferrimagnetic behavior) has been observed in the litera
ture to be approximately equal in molecules of m-tetradiphenylcarbene and d
iphenylearbene. (C) 2001 Elsevier Science B.V. All rights reserved.