Au3Si4- and Au4Si4: Electronically Equivalent but Different Polarity Superatoms

Kiichirou Koyasu, Kazuyuki Tsuruoka, Satoshi Kameoka, An Pang Tsai, Tatsuya Tsukuda

Research output: Contribution to journalArticlepeer-review

Abstract

A series of AuxSi4- cluster anions (x = 1-4) were generated most abundantly by laser ablation of a Au4Si alloy target. Photoelectron spectroscopy and density functional theory (DFT) calculation of AuxSi4- (x = 1-4) revealed that Au3Si4- can be viewed as an electronically closed superatom and is composed of a Si4 unit whose three adjacent edges of a single facet are bridged by three Au atoms. Such phase-segregated structure is facilitated by aurophilic interaction between the three Au atoms and results in a large permanent dipole moment (4.43 D). DFT calculations on an electronically equivalent superatom Au4Si4 predicted a new structure in which the uncoordinated Si atom of Au3Si4- is bonded by Au+. This Au4Si4 is much more stable than a cubic structure previously reported and has a large HOMO-LUMO gap (1.68 eV) and a small permanent dipole moment (0.41 D).

Original languageEnglish
Pages (from-to)7710-7715
Number of pages6
JournalJournal of Physical Chemistry A
Volume124
Issue number38
DOIs
Publication statusPublished - 2020 Sep 24

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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