Data produced during the development of a second-generation dual-mode X-band EPR resonator for rapid in-situ microwave heating

This dataset contains the COMSOL Multiphysics simulation with amplitude of the 100 kHz modulation magnetic field along a central cavity axis (sample located at 0 mm), The cavity’s flat walls are positioned at axial positions of ±7.5 mm; with the modulation coils positioned at ±9.5 to 11.5 mm. Each plot corresponds to pairs of copper laminates used for the flat cavity walls, of thicknesses 9, 18 and 35 mm. Also shown are the effects of a pair of 1 mm thick copper plates, which effectively extinguish the modulation field in the cavity space. The effect of no cavity walls is also shown (0 µm). Experimental results of this are also given.

This dataset also includes X-Band CW-EPR spectra of 20 mM Cu(acac)₂ solution in CHCl₃ recorded in a 1.6 mm EPR tube at 298 K (without filter), 318 K (without filter), 298 K (with filter), and 318 K (with filter). All spectra were acquired on the second-generation composite Cu/Al dual-mode cavity, employing 100 kHz field modulation and 0.1 mT modulation depth. The simulated spectra were used to calculate the rotational correlation times of the paramagnetic Cu(II) complex. Data measured for a 4 mm tube of the same sample, with the filter attached is also included.

S₁₁ measurements of the 9.5 GHz EPR mode on the second-generation dual-mode cavity without the low-pass filter attached to the heating port, showing the high loading on the EPR mode caused by amplifier circuit, and with the DC to 7.2 GHz low-pass filter connected directly to the heating port, thus resulting in negligible loading effect to the EPR mode, and subsequent improvement in the resulting EPR spectra.

Finally, S₁₁ measurements of the EPR mode when loaded with a 1.8 mm quartz tube filled with CHCl₃, at temperatures of 298 and 308 K. As temperature increases, the permittivity and microwave loss of the solvent decrease, causing a small increase in resonant frequency and increase in Q, resulting in the EPR mode becoming overcoupled.

Research results based upon these data are published at https://doi.org/10.1007/s00723-022-01463-1