Pseudo-Optical Modes in Room-Temperature Ionic Liquids

Autor(es)

Paschoal, Vitor H. ^[1] ; Ribeiro, Mauro C. C. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim, Dept Quim Fundamental, Lab Espectroscopia Mol, BR-05508000 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Journal of Physical Chemistry B; v. 124, n. 13, p. 2661-2667, APR 2 2020.
• Citações Web of Science: 0

Resumo

The terahertz spectrum encodes information about dynamics, structure, and intermolecular interactions of liquids being probed both experimentally and computationally by techniques such as Raman and far-infrared spectroscopies and molecular dynamics (MD) simulation. In the case of room temperature ionic liquids (RTILs), there has been a debate whether a mode observed at about 1.5-2.7 THz (50-90 cm(-1)) is due to a quasi-lattice structure or the formation of complex ions. Here we show through the analysis of Raman and far-infrared spectra and MD simulation of a typical RTIL that this mode has a collective optic-like character. Then, employing a simple model based on the theory for optical phonons in crystals, we show that a correlation between the frequency of this mode and material parameters holds for different RTILs. These results, which encompass a wide range of samples, reinforce a quasi-lattice view of the liquid phase. (AU)

• Processo FAPESP: 16/21070-5 - Espectroscopia vibracional com resolução espacial
• Beneficiário: Mauro Carlos Costa Ribeiro
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 15/07516-8 - Dinâmica coletiva de líquidos iônicos
• Beneficiário: Vitor Hugo Paschoal
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 19/00207-0 - Teoria do funcional da densidade aplicada a dinâmica vibracional de cristais de sistemas iônicos.
• Beneficiário: Vitor Hugo Paschoal
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado