Valence and Charge-transfer Optical Properties for Some Si_nC_m (m, n ≤ 12) Clusters: Comparing TD-DFT, Complete-basis-limit EOMCC, and Benchmarks from Spectroscopy

Authors

Jesse J. Lutz, ORISE Fellow
Xiaofeng F. Duan, Air Force Research Laboratory DoD Supercomputer Resource Center
Duminda S. Ranasinghe, University of Florida
Yifan Jin, University of Florida
Johannes T. Margraf, University of Florida
Ajith Perera, University of Florida
Larry W. Burggraf, Air Force Institute of TechnologyFollow
Rodney J. Bartlett, University of Florida

Document Type

Article

Publication Date

2018

Abstract

Accurate optical characterization of the closo-Si₁₂C₁₂ molecule is important to guide experimental efforts toward the synthesis of nano-wires, cyclic nano-arrays, and related array structures, which are anticipated to be robust and efficient exciton materials for opto-electronic devices. Working toward calibrated methods for the description of closo-Si₁₂C₁₂ oligomers, various electronic structure approaches are evaluated for their ability to reproduce measured optical transitions of the SiC₂, Si₂C_n (n = 1–3), and Si₃C_n (n = 1, 2) clusters reported earlier by Steglich and Maier [Astrophys. J. 801, 119 (2015)]. Complete-basis-limit equation-of-motion coupled-cluster (EOMCC) results are presented and a comparison is made between perturbative and renormalized non-iterative triples corrections. The effect of adding a renormalized correction for quadruples is also tested. Benchmark test sets derived from both measurement and high-level EOMCC calculations are then used to evaluate the performance of a variety of density functionals within the time-dependent density functional theory (TD-DFT) framework. The best-performing functionals are subsequently applied to predict valence TD-DFT excitation energies for the lowest-energy isomers of Si_nC and Si_n−1C_7−n (n = 4–6). TD-DFT approaches are then applied to the Si_nC_n (n = 4–12) clusters and unique spectroscopic signatures of closo-Si₁₂C₁₂ are discussed. Finally, various long-range corrected density functionals, including those from the CAM-QTP family, are applied to a charge-transfer excitation in a cyclic (Si₄C₄)₄ oligomer. Approaches for gauging the extent of charge-transfer character are also tested and EOMCC results are used to benchmark functionals and make recommendations.

Comments

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Plain-text title form: Valence and charge-transfer optical properties for some SinCm (m, n ≤ 12) clusters: Comparing TD-DFT, complete-basis-limit EOMCC, and benchmarks from spectroscopy.

Supplementary material for this work is available at the linked article page.

Funding note [excerpt]: This work was supported by funding from the U.S. DoD High Performance Computing Modernization Program and a grant of computer time at the U.S. Air Force Research Laboratory DoD Supercomputing Research Center

DOI

10.1063/1.5022701

Source Publication

The Journal of Chemical Physics

Recommended Citation

Lutz, J. J., Duan, X. F., Ranasinghe, D. S., Jin, Y., Margraf, J. T., Perera, A., … Bartlett, R. J. (2018). Valence and charge-transfer optical properties for some Si n C m ( m , n ≤ 12) clusters: Comparing TD-DFT, complete-basis-limit EOMCC, and benchmarks from spectroscopy. The Journal of Chemical Physics, 148(17), 174309. https://doi.org/10.1063/1.5022701