Calculation of the Infrared Frequencies as a Function of Temperature Using the Volume Data in the Ferroelectric Phase of NaNO₂

Abstract

We calculate the temperature dependence of the infrared frequencies of the TO and LO modes with the symmetries of A₁, B₁ and B₂ mainly in the ferroelectric phase of NaNO₂. This calculation is carried out using the volume dependence of the infrared frequencies through the mode Grüneisen parameter in this crystal. The volume dependences of the infrared frequencies are fitted to the observed frequencies by using constant mode Grüneisen parameter in the ferroelectric phase of NaNO₂. Our results show that this method of calculating the infrared frequencies describes the observed behaviour of NaNO₂ adequately.

Keywords:

• Infrared frequency
• bulk volume
• ferroelectric phase
• NaNO₂