The Jahn-Teller effect in C₆ F₆⁺

Recent results from the laser spectroscopy of C₆ F ₆⁺ are collected to derive the positions of ∼15 Jahn-Teller active vibronic levels of the four e_2g vibrational modes of the ground X̃ ²E_1g state. Intensity information is also collected for a number of transitions, both in absorption and emission, involving these modes. The data are analyzed by a model including linear and quadratic Jahn-Teller coupling, and coupling among all four of these active e_2g modes. The positions of these levels are predicted by the eigenvalues, and the transition intensities by the eigenvectors, of matrices of order ∼7000×7000. Quantitative agreement is obtained for both frequencies and intensities, thereby determining unperturbed oscillator frequencies, distortion constants, and stabilization energies for all the possible Jahn-Teller active modes of C₆F₆⁺. Combination of these results with a normal coordinate analysis gives the distorted geometry of the ion at the minimum of its potential function.