IR and UV Spectroscopic Analysis of C₂₀ Carbon Nanostructures

Abstract

Infrared (IR) and ultraviolet (UV) spectroscopic analysis of eight structural isomers of C₂₀ carbon nanostructures, i.e. ring, tadpole, bow-tie, dumb-bell, spiro, propellane, bowl and cage, were performed at different levels of theory including semi-empirical (AM1 and PM3), Hartree-Fock (HF/6-31++G, 6-31++G**) and density functional theory (B3LYP/6-31++G, 6-31++G**). A broad range of IR spectra (400-2700 cm^-1) is covered by C-C bending vibrations (low frequency region) and C-C stretching vibrations (high frequency region) in almost all isomers. The absorption maximum (λ_max) in UV spectra for bowl and cage isomers appears below 300 nm and for cyclic isomers above it. These results show that IR and UV spectra are useful tools for identification of C₂₀ structural isomers.<span id="transmark" style="display: none; width: 0px; height: 0px;"></span>