| Autor: |
Yonak, P., Kholod, O., Davydovych, V., Chornii, Yu., Kapustianyk, V. |
| Předmět: |
|
| Zdroj: |
Journal of Physical Studies; 2024, Vol. 28 Issue 3, p3701-1-3701-6, 6p |
| Abstrakt: |
This work analyzes variations in the chromophore group during the ferroelastoelectric phase transition in the (NH4)2CuCl4 · 2 H2O crystal using crystal field theory and the model of normalized spherical harmonics, based on the crystal's absorption spectra. For this purpose, a new version of the program package Crys Tool 2.0 was developed. It was shown that the anionic complex around Cu2+ ion possesses the shape of a flattened octahedron with the shortest distance O-Cu-O. The temperature dependences of the crystal field parameters as well as the metal-ligand distances show the continuous anomalies at the Curie point Tc = 200.5 K characteristic of the second-order phase transition. The transition to the ferroelastoelectric phase observed upon cooling is followed by an increase in the tetragonal distortion and a decrease in the rhombic distortion of the copper-halogen-hydrate octahedron. The relative values of the calculated metal-ligand distances correlate fairly well with the data of the X-ray diffraction study. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
