Mode-correlated product pairs in the F+CHD3→DF+CHD2 reaction

The title reaction was investigated at three different collision energies in a pulsed, crossed-beam apparatus. The (2+1) REMPI spectra of the CHD2 products revealed, in addition to the anticipated 4mn vibronic bands, a hitherto unobserved feature. The new feature was shown and assigned to the 311 band. A time-sliced ion velocity imaging technique was applied to map out the coincident DF attributes of the two product states 42 and 31, whose energy levels lie nearly degenerate. Remarkably similar results were found for the two states in every aspect at all three collision energies. A simple model of Fermi-coupled states was proposed to rationalize this, at first sight, surprising finding. Implications to collisional processes which involve mixed molecular basis states in general are outlined. Possible quantum interference phenomenon is suggested.