Abstract

In this research paper we examine the role played by the bending vibrational, modes of motion, delta (Cr-C-N) to influence the observed overall and relative vibronic intensity distribution for the E-2(g) --> (4)A(2g) phosphorescence of the Cr(CN)(6)(3-) complex ion. The calculation was carried out assuming both: (a) a seven-atom system model (molecular approximation) and (b) a negligible distortion from the octahedral symmetry for the system. The ligand polarization formalism was employed with reference to this system, since the ligand subsystems (CN)(-1) are highly polarizable and as a consequence a conventional crystal field calculation would be both unrealistic and unappropriate. This system was chosen since there is a solid evidence to conclude that vibrations of the same type in the tau (1u) and tau (2u) symmetry blocks induce comparable intensity. This is a clear indication that both the tau (1u) and tau (2u): delta (Cr-C-N) bending vibrations are exceptionally efficient to promote this radiative transition. This dynamical model is tested against the experimental data and it is shown that the model calculation, though approximate, gives results in excellent agreement with experiment.