Detailed ab-initio analysis of the magnetic coupling in CuF2

In this study, previously reported results on the magnetic coupling constan ts of CuF2 are completed. The most prominent coupling constants are determi ned qualitatively by UHF calculations on the 3D periodic system and more qu antitatively through accurate quantum chemical cluster calculations that ex plicitly include electron correlation effects. The magnetic ground state of CuF2 thus predicted is in agreement with experimental findings. For the do minant coupling constant, J(2), the value - 130 K is obtained. This value i s about five times larger than the CASCI or the UHF values themselves, show ing the importance of dynamical correlation effects. (C) 2000 Elsevier Scie nce B.V. All rights reserved.