Electron paramagnetic resonance of gamma irradiated [(CH3)(4)N]InCl4 and [(CH3)(4)N](2)CdCl4 single crystals

Abstract

Gamma irradiated [(CH3)(4)N]InCl4 and [(CH3)(4)N](2)CdCl4 single crystals were investigated by electron paramagnetic resonance at ambient temperature, and it has been found that both compounds indicate the existence of (CH3)(3)N+ radicals. The g factors were found to be isotropic, and the hyperfine constant for H atoms was measured as 2.86 mT and is isotropic for this radical in these substances. The hyperfine coupling constant of the N nucleus with the hole in (CH3)(3)N.+ in [(CH3)(4)N]InCl4 was found to be anisotropic with the A(zz) = 2.92, A(yy) - 1.62 and A(xx) = 1.40 mT. From these, it has been revealed that the C-3v-axis of (CH3)(3)N.+ radical performs rotational or jumping reorientational motions around a fixed axis, in addition to the rotations of protons in CH3 groups and the rotational motions of CH3 groups around the C-3v,-axis of the radical. The g, and the hyperfine coupling factors of the N nucleus were isotropic in (CH3)(3)N.+ in [(CH3)(4)N](2)CdCl4. This indicates the motional behaviour of the radical in this compound is as in a liquid. This isotropic behaviour of the hyperfine coupling constants was found to be same until the attainable lowest temperature of 113 K in our laboratory. (C) 2003 Elsevier Science Ltd. All rights reserved.