Splitting of the 2E(t 32) state of Cr(NH3)5X2+ ions significance of the coulombic parameter B

Abstract

The ²E(t³₂)↔⁴A₂ transition of a series of salts containing [Cr(NH₃)₅X]²⁺(X = Cl^–, Br^–, I^– ONO^–₂, ONO^–, CF₃COO^–, H₂O) ions has been measured in emission and absorption at temperatures down to 5 K. The splitting of the ²E state by the tetragonal perturbation is 100–300 cm^–1, an order of magnitude larger than predicted by conventional crystal field theory. It is suggested that the discrepancy arises from the d-orbital approximation used in evaluating the matrix elements of the Coulombic interaction. The vibronic intensity associated with the Cr—X stretching mode is discussed.