Calculation of ESR spin- spin relaxation times (1/T-2) transition metal ion complexes: A DFT application

Abstract

Only a limited experimental ESR research had been carried out in this field because high values of spin orbit constants of transition metal ions which provide an important energy transfer mechanism would affect the values of ESR parameters (especially Aten) of their complexes. Therefore, theoretical predictions were useful. DFT implemented in ADF: 2012.01 was applied by giving a set of commands like Single Point, LDA, Default, Spin Orbit, ZORA, Unrestricted, None, Collinear, Nosym using TZP or TZ2P Basis sets in its ESR/EPR/EFG/ZFS Program after optimization of each one of 141 complexes to obtain their ESR parameters: g11, g22, g33, giso, a11, a22, a33, Aten. ESR Spin- Spin Relaxation Times (1/T-2) whose values, to the best of our knowledge, were never reported before were, then, calculated from the giso values of the complexes.