Effects of non-collinear fine and hyperfine structure on the zero-field electron magnetic resonance of [Cu2(pmdien)2(N3)2][BPh4]2

Abstract

The zero-field electron magnetic spectrum of [Cu₂(pmdien)₂(N₃)₂][BPh₄]₂ has been analysed in terms of an electron spin triplet interacting with two equivalent nuclear spin quartets. The effect of non-collinear zero-field splitting and hyperfine tensors on the transition frequencies is emphasized for this particular spin system. The Euler rotation angles α and γ have little effect on the spectrum whereas β ≠ 0 leads to an effective reduction in A_z for the D – E and 2E branches of the triplet spectrum but has no effect on the D + E branch. Least-squares analysis produced spin-Hamiltonian parameters |D| = 2546.3 MHz, |E| = 450.1 MHz, |A_z| = 261.5 MHz and the angle β = 23.9°.