Bonding and singlet-triplet gap of silicon trimer : effects of protonation and attachment of alkali metal cations
© 2015 Wiley Periodicals, Inc.
| Veröffentlicht in: | Journal of computational chemistry. - 1984. - 36(2015), 11 vom: 30. Apr., Seite 805-15 |
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| 1. Verfasser: | |
| Weitere Verfasser: | , , , , , |
| Format: | Online-Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2015
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| Zugriff auf das übergeordnete Werk: | Journal of computational chemistry |
| Schlagworte: | Journal Article CCSD(T)/CBS CCSDT CCSDTQ G4 method electron localization function metal cation affinities proton affinity ring current silicon trimer |
| Zusammenfassung: | © 2015 Wiley Periodicals, Inc. We revisit the singlet-triplet energy gap (ΔE(ST)) of silicon trimer and evaluate the gaps of its derivatives by attachment of a cation (H(+), Li(+), Na(+), and K(+)) using the wavefunction-based methods including the composite G4, coupled-cluster theory CCSD(T)/CBS, CCSDT and CCSDTQ, and CASSCF/CASPT2 (for Si3) computations. Both (1)A1 and (3)A2' states of Si3 are determined to be degenerate. An intersystem crossing between both states appears to be possible at a point having an apex bond angle of around α = 68 ± 2° which is 16 ± 4 kJ/mol above the ground state. The proton, Li(+) and Na(+) cations tend to favor the low-spin state, whereas the K(+) cation favors the high-spin state. However, they do not modify significantly the ΔE(ST). The proton affinity of silicon trimer is determined as PA(Si3) = 830 ± 4 kJ/mol at 298 K. The metal cation affinities are also predicted to be LiCA(Si3) = 108 ± 8 kJ/mol, NaCA(Si3) = 79 ± 8 kJ/mol and KCA(Si3) = 44 ± 8 kJ/mol. The chemical bonding is probed using the electron localization function, and ring current analyses show that the singlet three-membered ring Si3 is, at most, nonaromatic. Attachment of the proton and Li(+) cation renders it anti-aromatic |
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| Beschreibung: | Date Completed 15.05.2015 Date Revised 26.03.2015 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1096-987X |
| DOI: | 10.1002/jcc.23856 |