Linear and Nonlinear Optical Response in Silver Nanoclusters: Insight from a Computational Investigation (Postprint)
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH WRIGHT-PATTERSON AFB United States
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We report a density functional theory DFT and time-dependent DFT TDDFT investigation of the thiolated silver nanoclusters Ag44SR304, Ag14SR12PR38, Ag31SG19, Ag32SG19, and Ag15SG11, which were synthesized and for which one-photon absorption OPA characterization is available. Our computational investigation based on careful examination of the exchange-correlation functional used in DFT geometry optimization and for the linear optical properties predictions by TDDFT, demonstrated good agreement with the measured linear absorption spectra, however dependent on the applied functional. Following the benchmarking, we evaluated the two-photon absorption TPA response using TDDFT, noting that accurate prediction of OPA is important for suppositions on the spectral range for TPA enhancement because of the sensitivity to the excitation energies. Although the TPA cross-section results are complicated by resonance effects and quantifying TPA cross sections for these systems is difficult, our results indicate that the nanoclusters Ag15 and Ag3132 are likely to have large TPA cross sections.
- Atomic and Molecular Physics and Spectroscopy