Description:
<jats:p>The <jats:sup>127</jats:sup>I NQR frequency in anilinium iodide C<jats:sub>6</jats:sub>H<jats:sub>5</jats:sub>NH<jats:sub>3</jats:sub>
<jats:sup>⊕</jats:sup>I<jats:sup>⊖</jats:sup> was studied at pressures up to 300 MPa and within the temperature range 77 K - 290 K. With increasing pressure the order-disorder transition point T<jats:sub>c</jats:sub> is shifted to higher temperatures. The pressure coefficient of the phase transition temperature amounts to dT<jats:sub>c</jats:sub>/dp = 4.2 x 10<jats:sup>-2</jats:sup> deg MPa<jats:sup>-1</jats:sup>. The pressure coefficient of the NQR frequency is negative. In addition, the <jats:sup>12'</jats:sup>I nuclear quadrupole coupling constants and the respective asymmetry parameters η were evaluated as a function of pressure. The results confirm the close connection between the mechanism of the phase transition and the dynamics of the N - H<jats:sup>⊕</jats:sup> ...I<jats:sup>⊖</jats:sup> hydrogen bonds.</jats:p>