Figure 3.

EPR absorption signal of Mn²⁺ (0.5 mM) detected using 2-pulse ESE field-sweep technique in frozen glass solution (H₂O/CH₃OH) at 10 K: (solid black) with no added bicarbonate; (dashed red) with 100 mM NaH¹²CO₃; (dashed green) with 100 mM NaH¹³CO₃. Vertical line indicates the magnetic field position (3490 G) at which ESEEM, ENDOR and HYSCORE measurements were carried out. Interpulse delay τ = 400 ns was used in the field-sweep experiments.