Broadband Transmission EPR Spectroscopy
Figure 15
Dependence on frequency and on cell length of aqueous tempo tranmission EPR.
Cells (cf Fig. 6) of 1215 cm (A), 300 cm (B) and 75 cm (C) were filled with 1 mM HO-tempo in 100 mM KCl. Spectra were collected at 0.1 GHz intervals from 0.8 GHz (upper trace) till 2.7 GHz (lower trace) as 500 averages of 10+10 s forward-reverse scans (i.e. circa 200 minutes per spectrum) over 200 gauss around the resonance field for g = 2 (i.e. 284±100 gauss for 0.8 GHz to 959±100 gauss for 2.7 GHz). In terms of maximal signal-to-noise the 12 m cell is seen to be optimal for frequencies approximately ≤ 1.1 GHz and the 3 m cell is optimal for circa 1.1–2.1 GHz. The 75 cm cell does not afford sufficient signal under the used conditions.