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Electronic Spectra and Crystal Structure of the Layered Compounds (C n H 2 n +1 NH 3 ) 2 CuCl 4 ( n = 2, 3) in the Region of Their Phase Transitions
Author(s) -
Kapustianik V.B.,
Bazhan V.V.,
Korchak Yu.M.
Publication year - 2002
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/1521-3951(200211)234:2<674::aid-pssb674>3.0.co;2-2
Subject(s) - crystal (programming language) , harmonics , crystallography , halogen , phase (matter) , absorption spectroscopy , octahedron , phase transition , distortion (music) , field (mathematics) , spectral line , chemistry , spherical harmonics , metal , condensed matter physics , crystal structure , materials science , optics , physics , mathematics , cmos , voltage , amplifier , computer science , alkyl , quantum mechanics , organic chemistry , astronomy , programming language , optoelectronics , pure mathematics
On the basis of absorption spectroscopy data the temperature evolution of Cu 2+ ion environment in the layered compounds (C n H 2 n +1 NH 3 ) 2 CuCl 4 ( n =2, 3) was studied. For the detailed analysis of experimental data the special program package CrysTool 1.0 based on quantum mechanical models using normalized spherical harmonics (NSH) has been created. It has been found that both crystals contain tetragonally distorted octahedral metal–halogen complexes and that the degree of distortion is less pronounced in the low‐temperature phases. The phase transitions (PTs) in both compounds were found to be connected with gradual ordering of the organic cations at cooling. For (C 2 H 5 NH 3 ) 2 CuCl 4 the parameters of crystal field, normalized spherical harmonics, and angular overlap model as well as the metal–halogen distances show jump‐like anomalies at the points of PTs ( T 1 = 364 K and T 2 = 356 K, at heating), whereas a continuous change was observed at T 3 = 330 K.