Jahn-Teller effects in EPR of a square planar copper complex

An unusual temperature dependence of the EPR parameters of copper(II) and oxovanadium(IV) bis(acetylacetonate) complexes

“…This is a consequence of mixing of excited states with the d x 2 y 2 ground state of the Cu(II) ion. 7,8,27 Vibronic coupling effects have also been found to influence the temperature dependence of Mössbauer spectroscopy parameters. 28,29 The temperature-dependent ligand field makes a small contribution; a ca.…”