Abstract
The temperature dependencies of the refractive and dilative characteristics of diglycine nitrate crystals (CH2NH2COOH)2ċHNO3 (DGN) have been analyzed for three principal directions of optical indicatrix in the temperature ranges of ferroelectric phase transitions, Tc = 206 K. By means of generalizing the Lorenz-Lorentz relation for effective electric field the characteristic coefficient x of the intermolecular interaction was analyzed for the different directions of light polarization in DGN crystal.