RESUMO
In this work we use the ab initio calculations to study the intercalation of lithium (Li) atoms in the channels of the single-wall boron nitride nanotube (BNNT) bundles. The relaxed structure as well as the electronic band structure were obtained. Results reveals that Li insertion modifies the band structure by shifting the Fermi energy to conduction band. The Li atoms act as electron donors and this modifies the electronic properties of the BNNT bundles due the intercalation. The electronic properties changes induced in the effects are dependent on Li atom numbers per nanotube.
RESUMO
RbNd(WO(4))(2) was investigated by high pressure Raman spectroscopy in the 0.1-12.3 GPa pressure interval. The assignment of modes was made based on lattice dynamics calculations and the results of these calculations helped us to also discuss the high pressure behavior of phonon spectra in this material. Our results show that a double oxygen bridge plays a fundamental role in the vibrational properties of this system. A density functional theory (DFT) calculation of hydrostatic pressure effects on RbNd(WO(4))(2) was performed in order to understand the effect of internal bond changes on the vibrational properties of RbNd(WO(4))(2). No pressure induced structural phase transition was observed in the Raman study at room temperature, and the DFT calculation (T = 0 K) is consistent with this result. The anomalous softening of the bridge stretching mode at 770 cm(-1) was attributed to the decrease of W-O1-W bond angle with increasing pressure.