Task: Text Categorization
Input (English): The cooperative pseudo- form of this phenomenon has been linked to the vibronic theory of ferroelectricity. A version of this phenomenon arising from mixing of two or more interacting states was studied by Opik and Pryce. The Ham factor is used to simplify calculations of electronic and vibronic properties affected by this phenomenon. It is frequently observed in complexes where the e-sub-g orbitals contain an odd number of electrons, as in compounds of copper(II). For 10 points, name this effect in which nonlinear systems in a degenerate electronic state distort to remove the degeneracy, which can result in the distortion of a coordination compound with octahedral symmetry to tetragonal geometry. 
Output (English): Science