A vibronic coupling approach for the interpretation of the g-value temperature dependence in type-I copper proteins

Abstract

The e.s.r. spectra of copper proteins containing type-I (pseudo-tetrahedral) centres show a gradual decrease of the g‖ values with increasing temperature. This fact is interpreted on the basis of a vibronic coupling mechanism which is effective in pseudo-tetrahedral copper(II) complexes, but not in the square-planar ones. A theory is developed to account for the shift of the g‖ values as well as for the d-d transition energies. A functional role of the vibronic coupling is also suggested.