Parameters of paramagnetic relaxation were determined by OD ESR and quantum beats techniques for a recombining pair of radical ions (DPS-d10)+/(PTP-d14)− inn-hexane, isooctane,cis-decalin, and squalane solutions. The T2 relaxation time determined by quantum beats technique is independent of solvent viscosity and magnetic field strength in the range 170–9600 G. These data are in agreement with the results obtained by OD ESR technique assuming fastT 1 relaxation for radical cation. Neglecting the contribution of radical anion relaxation, we obtained T1c=T2c≅50 ns for (DPS-d10)+.
Appl.Mag.Res. 1997, V.12, No.4, pp. 505-512

The fractions Θβ and ΘX of spin-correlated singlet radical-ion pairs in alkane solutions irradiated by β-particles and X-rays were got from experiments on magnetic field effects and quantum beats in recombination fluorescence. The ratio Θβ/ΘX values of 1.3−2.8 for the solvent series studied were found both from magnetic effect and quantum beats. The Monte Carlo calculations were made to explain the variations of Θβ/ΘX in different solvents. The high value of Θβ/ΘX = 2.8 for isooctane is probably due both to large separation between ions in pair and to high concentration of neutral radical in the spur.
Radiat.Physi.Chem. 1998, V.51, No.1, pp. 31-36

The quantum beats and magnetic field effect on the reaction yield spectroscopy techniques were employed to study the formation of diphenyl sulfide radical cations in squalane solutions under ionizing irradiation. It is demonstrated that the precursors of diphenyl sulfide radical cations are short-lived primary solvent radical cations (holes) with the electron spin resonance spectrum narrowed by the resonance charge transfer reaction. The rate constant of hole scavenging by diphenyl sulfide molecules was measured directly and amounts to 6.1 × 109 M-1 s-1, exceeding the diffusion-controlled one several times. The obtained value is well in line with the data on pulse radiolysis of squalane solutions with optical monitoring of the highly mobile precursor, supporting the hypothesis about the hole nature of the latter.
J.Phys.Chem. A, 1997, V.101, No.42, pp.7711-7717

Quantum beats caused by the hyperfine coupling (hfc) with magnetically equivalent protons were observed in the recombination fluorescence of the singlet-correlated pairs of secondary radical ions generated in cyclohexane solutions by ionizing radiation. In agreement with theoretical predictions, the ratio IH(t)/I0(t) of fluorescence decay kinetics in high and zero magnetic fields showed narrow peaks for the radical cations with an even number of the equivalent protons. To generate radical pairs, p-terphenyl-d14 was used as an electron acceptor while the solvent holes were trapped by octamethyl-1,4-cyclohexadiene, tetramethylethylene, 9,10-octalin, cis-decalin, hexamethylbenzene, durene, p-diethylbenzene, p-xylene, or benzene. When diisopropylamine was used as a hole acceptor, a trough was observed instead of the strongest peak. The position of the strongest peak (trough) is determined by the value of hfc constant only and is independent of the number of protons.
Chem.Phys. 2000, V.255. No. 2-3, pp.237–245