Electron Spin Resonance Spectrometry Protocol

Following our works,^{22 (link)–29 (link), 31 , 36 (link)–38 (link)} a Varian Century Series X-band (9.3 GHz) ESR spectrometer with an E-4531 dual cavity, 9-inch magnet, and a 200 mW Klystron was used for the ESR studies. For the field calibration, Fremy’s salt (g_center = 2.0056, A(N) = 13.09 G) was employed. All ESR spectra were recorded at 77 K and at microwave power of 40 dB (20 μW). Recording of ESR spectra at 77 K maximizes the signal height and allows for comparison of signal intensities. For recording and digital storage of EPR spectra and for spectral analyses, we used our in-house developed programs (ESRTAK and ESRADSUB). To obtain a simulated spectrum that matches the corresponding experimentally recorded spectrum, we employed the Bruker programs (WIN-EPR, SIMFONIA).^{22 (link)–29 (link), 31 , 36 (link)–38 (link)}