Infrared Spectroscopy of Quaterthiophene Confined Inside Single-Walled Carbon Nanotubes

Combining molecular dynamics (MD) and density functional theory (DFT), we investigate here the Infrared (IR) spectra of the hybrids based on single-walled carbon nanotubes (SWCNTs) encapsulating quaterthiophene molecule (4T). We calculate the IR spectra of SWCNTs and 4T molecule before and after encapsulation. An attentive analysis of the nanocon-finement effect on IR spectra of 4T molecule and SWCNTs with optimized diameter allows us to point out the different modifications that characterize the intermolecular interactions between 4T and SWCNTs in the hybrid systems (4T@SWCNTs). It is demonstrated that the most significant changes occur in the low-wavenumber range, and the calculated IR responses of 4T@SWCNT hybrids suggest the possibility of charge transfer from the SWCNTs to the confined 4T. These predictions are useful to interpret the experimental IR spectra of such hybrids.