Applied to a 3 (MeO) 2 cluster by Valiev and co-workers found rate constants between 10 12 -10 14 s -1 for various S m → S 0 transitions. Merzlikin and co-workers calculate internal conversion for azatrioxa circulene and heptamethine cyanine, and found rates of 1 × 10 7 s -1 and 1 × 10 respectively. Interestingly, these authors also looked at mixing the electric dipole operator with the nonadiabatic operator, and found that while the contribution was weak (<1 s -1 ), a strong electric field could strong perturb the rate of internal conversion, though this phenomenon has been known for some time . Baryshnikov and co-workers studied five porphyrin derivatives, and for all but one calculated rate constants comparing well with experiment.