CANCELLATION OF DIVERGENT TERMS IN RELATIVISTIC THEORY OF MAGNETIC PROPERTIES

D.G. ZACCARI; M.C. RUIZ DE AZUA; J. I. MELO; C. G. GIRIBET

Merlo, San Luis, Argentina

Congreso; 91 Reunion Anual de la Asociacion Fisica Argentina; 2006

Asociacion Fisica Argentina

  Relativistic effects on molecular magnetic properties can be of great importance in heavy atom containing compounds. This is particularly true for properties depending heavily on the electronic density in the vicinity of the atomic nucleus. We work in this subject within a close collaboration with the group of Dr. G. A. Aucar of "Universidad Nacional del Nordeste". In recent work [1], a unitary transformation of the magnetic field dependent Dirac hamiltonian was proposed, which minimizes the coupling of the large and small components of 4-component spinors and leads to mathematical expressions of the magnetic interaction which closely resemble the non-relativistic counterparts. However, such transformation leads to divergent expressions of individual terms when the magnetic field of a point nucleus is considered [2]. In this work we verify the validity of the mentioned unitary transformation for this case, in the sense of mathematical distributions at the 4-component level. The cancellation of divergent terms is explicitly shown by considering the "correct" magnetic field of this case. It is concluded that, although individual terms yield divergent values, the overall result should be finite and consistent with that of other formalisms.    1.      L. Visscher, Adv. Quantum Chem., 48, chap. 19 (2005). W. Kutzelnigg, Phys. Rev. A 67, 32109 (2003).