%0 Journal Article %1 WOS:000270692700010 %A Coelho, Santos J %A Paraguassu, W %A Maczka, M %A Filho, A G Souza %A Freire, P T C %A Filho, J Mendes %A Hanuza, J %C 111 RIVER ST, HOBOKEN 07030-5774, NJ USA %D 2009 %I WILEY %J JOURNAL OF RAMAN SPECTROSCOPY %K bronzes; calculation; ferroelectric; hexagonal hydrostatic phonon pressure} scattering; valence-balanced {Raman %N 9 %P 1150-1157 %R 10.1002/jrs.2248 %T Vibrational studies of hexagonal bronze systems: phonon calculation and high pressure induced phase transformation %V 40 %X Hexagonal bronzes and valence-balanced hexatungstates (VBHT) have attracted great attention for presenting rich polymorphism and displaying superconductor or ferroelectric properties. In the present work, structural and vibrational properties of RbBi1/3W8/3O9 (RBW) crystal (VBHT type) were investigated by high-pressure Raman scattering experiments. The results suggest the existence of a reversible pressure-induced structural phase transition at about 4 GPa. This transformation is most likely related to rotations of octahedral units along the c-axis with no abrupt changes of apical O-W-O bonds length. In order to get further understanding of RBW vibrational properties, we performed phonon calculations, by using classical lattice dynamics, in the related hexagonal structure of the K0.26WO6 system. These calculations revealed that most of vibrational properties of K0.26WO6 are governed by tubular `like' vibrations of the hexagonal cavity, which resemble similar vibrations of tubular nanostructures. The pressure dependence of Raman modes is understood in terms of calculated phonon eigenvectors at ambient pressure. Copyright (C) 2009 John Wiley & Sons, Ltd.

@article{WOS:000270692700010, abstract = {Hexagonal bronzes and valence-balanced hexatungstates (VBHT) have attracted great attention for presenting rich polymorphism and displaying superconductor or ferroelectric properties. In the present work, structural and vibrational properties of RbBi1/3W8/3O9 (RBW) crystal (VBHT type) were investigated by high-pressure Raman scattering experiments. The results suggest the existence of a reversible pressure-induced structural phase transition at about 4 GPa. This transformation is most likely related to rotations of octahedral units along the c-axis with no abrupt changes of apical O-W-O bonds length. In order to get further understanding of RBW vibrational properties, we performed phonon calculations, by using classical lattice dynamics, in the related hexagonal structure of the K0.26WO6 system. These calculations revealed that most of vibrational properties of K0.26WO6 are governed by tubular `like' vibrations of the hexagonal cavity, which resemble similar vibrations of tubular nanostructures. The pressure dependence of Raman modes is understood in terms of calculated phonon eigenvectors at ambient pressure. Copyright (C) 2009 John Wiley & Sons, Ltd.}, added-at = {2022-05-23T20:00:14.000+0200}, address = {111 RIVER ST, HOBOKEN 07030-5774, NJ USA}, author = {Coelho, Santos J and Paraguassu, W and Maczka, M and Filho, A G Souza and Freire, P T C and Filho, J Mendes and Hanuza, J}, biburl = {https://www.bibsonomy.org/bibtex/2903841a57156e7216a84cdd2067cf638/ppgfis_ufc_br}, doi = {10.1002/jrs.2248}, interhash = {03a8d7c71250680942be75bf247e90af}, intrahash = {903841a57156e7216a84cdd2067cf638}, issn = {0377-0486}, journal = {JOURNAL OF RAMAN SPECTROSCOPY}, keywords = {bronzes; calculation; ferroelectric; hexagonal hydrostatic phonon pressure} scattering; valence-balanced {Raman}, number = 9, pages = {1150-1157}, publisher = {WILEY}, pubstate = {published}, timestamp = {2022-05-23T20:00:14.000+0200}, title = {Vibrational studies of hexagonal bronze systems: phonon calculation and high pressure induced phase transformation}, tppubtype = {article}, volume = 40, year = 2009 }