Magnetic behavior of the organic polymers m-polydiphenylcarbene by the Hubbard model

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.