FIGURE 5.

TNP-AMP superfluorescence of E1Ca₂·BeF_x and E2·BeF₃⁻. E1Ca₂·BeF_x and E1Ca₂·AlF_x were produced in 50 μm Ca²⁺ and 15 mm MgCl₂, then at 25 (A) and 4 °C (B), a small volume of TNP-AMP was added to give saturating 4 μm, and the TNP-AMP fluorescence was followed. The fluorescence of E2·BeF₃⁻ produced with BeF_x in the absence of Ca²⁺, the E1Ca₂ and E2 states without the fluoride compounds, and without SR vesicles (no SRV) were also followed. C, the TNP-AMP fluorescence intensities were measured at various concentrations of TNP-AMP at 25 °C, otherwise as described for A. For E1Ca₂·BeF_x, the maximum level of transient superfluorescence was determined by extrapolating its decrease to the time of TNP-AMP addition. In the lower panel in C, the low fluorescence was replotted on the expanded scale. The maximum fluorescence intensities at saturating 4 μm TNP-AMP were obtained by subtracting the background level without TNP-AMP and the level of 4 μm TNP-AMP without the SR vesicles, and given as the relative values in Table 1.