THE ELECTRONIC ENERGY TRANSFER BETWEEN (CO)-C-12 (A (1)Pi) and (CO)-C-13 (X (1)Sigma(+)) STUDIED BY REMPI SPECTROSCOPY

The energy transfer processes between (co)-c-12(a(1)pi) and (co)-c-13(x (1)sigma(+)) were studied at 77 k by using the technique of two-color resonance enhanced multiphoton ionization spectroscopy. in a static cell with a mixture of 0.92 (co)-c-13 + 0.08 (co)-c-12, (co)-c-12 molecules were populated to the a state by 2-photon excitation using an uv dye laser. the (co)-c-13(a) resulted from the collision e-e energy transfer were detected by co(a)-> co(b)-> co+ (x) 2-step ionization using a visible dye laser. the energy transfer processes were found to be very fast with total cross sections of 114 +/- 42, 22 +/- 4, 17 +/- 6 angstrom(2) for (co)-c-12(a) v=1,2,3 respectively. we found that for different vibrational channels, cross section decreases with increasing energy mismatch delta e. another interesting result is that, for the lambda doublet, the production of pi(+) is always larger than that of pi(-). the formation of an intermediate exciplex [occo]* is proposed to explain the experimental results.