The Distribution Change of Relaxation Times in ³⁵Cl NQR for Phase Transitions in p-Dichlorobenzene

Abstract

The results of an experimental study of phase transitions in molecular crystal of paradichlorobenzene by the nuclear quadrupole resonance relaxometry method with inversion of the Laplace transform are described in the article. The distributions of relaxation times T ₁, T _1ρ and $T_{2}^{*}$ for α- and β-phases of p-C₆H₄Cl₂ are measured. It is determined, that spin–spin relaxation times have unimodal distributions for α- and β-phases, and spin–lattice relaxation times, including in rotating system of coordinates—multimodal distributions. It has been shown that spontaneous β → α phase transition does not arise in the porous material preliminary impregnated with the fused sample and the β-phase is steadily retained.