S–T conversion induced by external magnetic field in gaseous oxalylfluoride excited to the 7151-level of the à 1Au state

Abstract

Fluorescence decay of gaseous oxalylfluoride (COF)2 excited to the à 1Au(7151) level was measured as a function of gas pressure in absence and in presence of magnetic field, B=0.3 T. On excitation to this level, the dynamics in both zero and nonzero fields may be described in the intermediate-molecule limit, with the fluorescence exhibiting biexponential and triexponential decay, respectively. The fast component decay rate constant kf=(5.31±0.22)⋅107 s−1 is independent on the (COF)2 gas pressure or magnetic field strength, while that of the first slow component depends on both. The second slow component lifetime is independent of the field strength, while dependent on the gas pressure. The Stern–Volmer dependence, measured with a field in the 0.3–12 mTorr pressure range, is nonlinear. The results obtained were explained by the indirect (electronic- and nuclear-spin-decoupling) mechanism, proposed earlier.