A comment on “ESR linewidth studies on naphthalene ion in low bulk dielectric constant media”

It is noted, if one uses the lineshape analysis for unresolved hyperfine splitting proposed by Jones et al. that one must be careful to avoid lineshape distortion from the magnetic field modulation amplitudes and frequencies used. At 100 kHz field modulation the lineshape distortion is significant for linewidths less than ≈ 350 mG and unresolved hyperfine splittings less than ≈ 70 mG.