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A 35 Cl NQR Study of [(CH 3 ) 2 NH 2 ] 2 SeCl 6 Crystals
Author(s) -
Horiuchi K.
Publication year - 1993
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/pssb.2221780111
Subject(s) - octahedron , line (geometry) , chemistry , activation energy , analytical chemistry (journal) , phase (matter) , spectral line , crystallography , crystal structure , physics , mathematics , geometry , organic chemistry , chromatography , astronomy
The temperature dependence of the 35 Cl NQR frequencies in [(CH 3 ) 2 NH 2 ] 2 SeCl 6 is measured between 78 and 300 K. Two NQR lines with intensity ratio of 2:1 are observed at 196 K. The low‐frequency line fades out below about 80 K, while the other line is still clearly observed. This arises from a second‐order structural phase transition in which the librational modes of [SeCl 6 ] 2− anions become soft. Both lines fade out at higher temperature, however, the low‐frequency one at 26 K lower than the other one. This is explained by the C 4 reorientional motions of the octahedral anions having a relative low activation energy of 18 kJ mol −1 .