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[5574] Artykuł: Studies of absorption spectra of A2MCl4 (M=Cu, Co) crystals with organic cationsCzasopismo: Ferroelectrics Tom: 239, Zeszyt: 1, Strony: 189-196ISSN: 0015-0193 Wydawca: TAYLOR & FRANCIS LTD, 4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND Opublikowano: 2000 Autorzy / Redaktorzy / Twórcy
Grupa MNiSW: Materiały z konferencji międzynarodowej (zarejestrowane w Web of Science) Punkty MNiSW: 0 Klasyfikacja Web of Science: Article; Proceedings Paper Pełny tekst DOI Web of Science Keywords: incommensurate phase  phase transition  optical spectroscopy  A2MX4 crystals  absorption spectra  |
The optical spectra (200-20000 cm−1) of A2MCl4 + of A2MCl4 (A=NH4 +, N(CH3)4 +, NH(CH3)3 +, NH2(CH3)2 +, N(C2H5)4 +, NH2(C2H5)2 +, NH3(C2H5)+N(CH3)4 +; M=Cu, Co) ferroelectric crystals with organic cations at different temperatures have been investigated. Using Gaussian analysis and Tanabe-Sugano diagram, the absorption maximum positions and the electron transitions have been determined. The experimental results have been discussed based upon theory of the crystalline field. It means, that the structural phase transitions exist in the material. In some of these crystals the thermochromic effects as results of structural phase transitions have been observed. The phenomenon of phase transition in [NH2(C2H5)2]2CuCl4 with change of colour from green to yellow can be used for production of ultraviolet detectors.