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Title: Benchmarking the Fundamental Electronic Properties of small TiO 2 Nanoclusters by GW and Coupled Cluster Theory Calculations

We study the vertical ionisation potential, electron affinity, fundamental gap and exciton binding energy values of small bare and hydroxylated TiO 2 nanoclusters to understand how the excited state properties change as a function of size and hydroxylation. In addition, we have employed a range of many-body methods; including G 0 W 0, qs GW, EA/IP-EOM-CCSD and DFT (B3LYP, PBE), to compare the performance and predictions of the different classes of methods. We demonstrate that for bare (i.e. non-hydroxylated) clusters all many-body methods predict the same trend with cluster size. The highest occupied and lowest unoccupied DFT orbitals follow the same trends as the electron affinity and ionisation potentials predicted by the many-body methods but are generally far too shallow and deep respectively in absolute terms. In contrast, the ΔDFT method is found to yield values in the correct energy window. However, its predictions depend on the functional used and do not necessarily follow trends based on the many-body methods. The effect of hydroxylation of the clusters is to open up both the optical and fundamental gap. In conclusion, a simple microscopic explanation for the observed trends with cluster size and upon hydroxylation is proposed in terms of the Madelungmore » onsite potential.« less
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [4] ; ORCiD logo [5] ; ORCiD logo [6]
  1. Imperial College, London (United Kingdom); Univ. College London, London (United Kingdom)
  2. Karlsruhe Institute of Technology, Karlsruhe (Germany)
  3. Louisiana State Univ., Baton Rouge, LA (United States)
  4. Univ. Catholique de Louvain, Louvaine-la-Neuve (Belgium)
  5. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  6. Univ. College London, London (United Kingdom)
Publication Date:
Report Number(s):
PNNL-SA-125647
Journal ID: ISSN 1549-9618; KP1704020
Grant/Contract Number:
AC05-76RL01830; AC06-76RL01830; SC0012432
Type:
Published Article
Journal Name:
Journal of Chemical Theory and Computation
Additional Journal Information:
Journal Volume: 13; Journal Issue: 8; Journal ID: ISSN 1549-9618
Publisher:
American Chemical Society
Research Org:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; electronic structure theory
OSTI Identifier:
1371788
Alternate Identifier(s):
OSTI ID: 1390409