Theoretical study of linear and non-linear optical properties of small CaCn (n = 2�7) clusters

The linear and NLO properties of small calcium doped carbon cluster CaC<inf>n</inf> (n = 2�7) were investigated in the framework of time-dependent density functional theory (TD-DFT) with CAM-B3LYP/6-311+G(d). The absorption wavelength (?), oscillatory strength (f), transition energy (E<inf>ex</inf>), and nature of transitions of major excitations have been calculated. It was shown that the most intense peak was fall in the UV region of the spectrum. The most intense peaks among all studied clusters for CaC<inf>6</inf>was found at 230 nm with oscillatory strength of 0.261, and excitation was due to H-2 ? L, H-1 ? L + 1, H ? L + 13 transition. We observe a few peaks with weaker peaks in the visible region for CaC<inf>2</inf>, CaC<inf>5</inf>, and CaC<inf>7</inf>at560 nm, 525 nm, and 467, respectively. The average polarizability ? and first hyperpolarizability ?<inf>tot</inf> have been calculated and found that the polarizability of studied clusters increases with the number of carbon atoms in the cluster. Hyperpolarizability of CaC<inf>2</inf> and CaC<inf>5</inf> was calculated as 2874.7 a.u. and 1329.9 a.u. Indicating strong NLO prospects among all studied clusters. The optical response of studied clusters suggests that these materials can be considered as auspicious for optoelectronic devices. � 2024 Elsevier B.V., All rights reserved.