A theoretical study on photo absorption in silicon decorated boron clusters (B_nSi, n=7-10)

In this work, we have studied the optical absorption spectra of small boron clusters doped with single silicon atom (B_nSi, n=7-10) and is reported employing CAM-B3LYP functional with 6-311+G(d) basis –set within the framework of time dependent density functional study (TD-DFT). We have computed excitation energy, oscillator strength, wavelength and the corresponding orbital transitions associated with a given oscillator strength. Analysis of optical absorption spectra of studied clusters shows that most of the absorption peaks are found in the ultraviolet-visible (UV-Vis) region (200 nm-700 nm). The major peaks are found to fall in UV region along with some weaker peaks at visible region. The most intense peak is recorded for B8Si cluster at 232 nm and oscillator strength of 0.084. This peak is associated with the orbital transition from H-4→L+1.