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Using a first-principles approach based on density functional theory,this paper studies the electronic and dynamical properties of β-V2O5.A smaller band gap and much wider split-off bands have been observed in comparison with αV2O5.The Ramanand infrared-active modes at the Γ point of the Brillouin zone are evaluated with LO/TO splitting,where the symbol denotes the longitudinal and transverse optical model.The nonresonant Raman spectrum of a βV2O5 powder sample is also computed,providing benchmark theoretical results for the assignment of the experimental spectrum.The computed spectrum agrees with the available experimental data very well.This calculation helps to gain a better understanding of the transition from αto β-V2O5.
Using a first-principles approach based on density functional theory, this paper studies the electronic and dynamical properties of β-V2O5.A smaller band gap and much wider split-off bands have been observed in comparison with αV2O5. Raman and infrared-active modes at the Γ point of the Brillouin zone are evaluated with LO / TO splitting, where the symbol denotes the longitudinal and transverse optical model. The nonresonant Raman spectrum of a βV2O5 powder sample is also computed, providing a benchmark theoretical result for the assignment of the experimental spectrum. The computed spectrum agrees with the available experimental data very well. This calculation helps to gain a better understanding of the transition from .alpha.-V2O5.