Raman scattering and optical properties of lithium nanoparticles obtained by green synthesis

The first report on lithium nanoparticles synthesized experimentally is presented. The nanoparticles were obtained using the extract of Opuntia ficus-indica through “green synthesis”. The optical, structural and vibrational properties were studied through optical absorption, TEM microscopy and Raman spectroscopy. The particles show a size of approximately 5 nm. The absorption bands were found at 315 and 415 nm in the samples after the synthesis of the nanoparticles. One Raman band was detected at around 280 cm−1. Several levels of approximation of the density functional theory and the Hartree–Fock method on the structural and vibrational study of the lithium clusters (Lin, n = 2–18) are incorporated. A radial breathing mode (RMB) type Raman mode was found for the case Lin (n > 3) in the predicted Raman spectrum. This mode shows the highest relative intensity for each case, and a shift to lower wavenumbers when the amount of atoms in the cluster increases.