Single crystal EPR of Cu(C5H5NO)6(BF4)2:: an example of admixed ground state

Single crystal electron paramagnetic resonance (EPR) of Cu(C5H5NO)(6)(BF4)(2) is studied at 300 K. The spin Hamiltonian parameters obtained at 300 K are A(11) = - 149.8, A(22) = - 50.7 and A(33) = - 37.7 (all in units of 10(-4) cm(-1)), g(11) = 2.3452, g(22) = 2.0679 and g(33) = 2.0695. Angular Variation of hyperfine structure lines shows the presence of a single magnetic site. The low magnitude of the A(11) value for Cu(C5H5NO)(6)(BF4)(2) is rationalized in terms of a mixed d(x2.y2)/d(z2) ground state. (C) 2000 Elsevier Science B.V. All rights reserved.