Electron-spin-relaxation times in Se-doped potassium dihydrogen phosphate ferroelectric crystals

Impact of Electronic Asymmetry on Photoexcited Triplet-State Spin Distributions in Conjugated Porphyrin Oligomers Probed via EPR Spectroscopy

“…Electron spin lattice relaxation (SLR) times were determined using progressive microwave power saturation. The spectral intensity maxima of the canonical transitions (Z I and Z II ) as a function of the square root of the microwave power were analyzed using the methods described by Wheeler et al 41…”

Electron spin relaxation governed by Raman processes both for Cu2+ ions and carbonate radicals in KHCO3 crystals: EPR and electron spin echo studies

“…It was found for F-centers in KCl, where the Debye temperature was determined as H D = 210 K [17], and in KBr [18]. The relaxation of SeO 3À 4 radical in KH 2 PO 4 crystals was described as due to the Raman process with H D = 119 K [19]. The Raman process was also suggested as responsible for the relaxation of trityl radicals in water-glycerol frozen solution up to 100 K [20].…”

Electron Spin Relaxation of Hole and Electron Polarons in π-Conjugated Porphyrin Arrays: Spintronic Implications

“…Using an individual hyperfine line of [PZnE 2 ] –• , a lower estimate of the T 2 relaxation time at ∼40 ns may be determined using T 2 = 2/(3 1/2 γΔ B pp ) = 65.6 (G ns)/Δ B pp , where γ is the gyromagnetic ratio for the electron and Δ B pp is the peak-to-peak line width. Using this value and a value of B 1/2 obtained from the saturation profile (Figure B), an upper limit for the T 1 relaxation time for [PZnE 2 ] –• can be estimated at ∼700 ns at 298 K using T 1 = 1/( T 2 γ 2 B 1/2 2 ), where γ is the magnetogyric ratio for the electron, with B 1/2 and T 2 as defined above …”

“…The microwave saturation data were collected generally under slow passage conditions (T 1 T 2 ) 1/2 ≪ B 1 /ω m ΔB pp ) at 298 K (i.e., the time between successive field modulation cycles is sufficiently long for each spin packet to relax between cycles), where B 1 is the microwave magnetic field strength, ω m is the modulation frequency, and ΔB pp is the peakto-peak line width. Saturation data were fitted to a model originally developed by Portis 50 and Castner 48 and elaborated by Zhidkov 51 and Wheeler, 52 yielding the microwave field in the rotating plane at half-saturation (B 1/2 ) of the resonance line and a homogeneity factor b, the value of which has extremes at b = 1 for line shapes determined by complete inhomogeneous broadening and b = 3 for homogeneously broadened line shapes. Saturation profiles for these extremes and for cases in between are shown in Figure S2 (Supporting Information).…”

“…Using this value and a value of B 1/2 obtained from the saturation profile (Figure 2B), an upper limit for the T 1 relaxation time for [PZnE 2 ] −• can be estimated at ∼700 ns at 298 K using T 1 = 1/(T 2 γ 2 B 1/2 2 ), where γ is the magnetogyric ratio for the electron, with B 1/2 and T 2 as defined above. 52 Progressive microwave power saturation profiles for S5A,B). For [PZn 1 ] +• , the saturation at high microwave powers is indicative of an inhomogeneously broadened line shape that is derived from unresolved nuclear hyperfine interactions stemming primarily from the pyrrole nitogens.…”