TY - JOUR

T1 - A new look at the structure of the neutral Au18 cluster: hollow versus filled golden cage

AU - Nhat, Pham Vu

AU - Si, Nguyen Thanh

AU - Fielicke, André

AU - Kiselev, Vitaly G

AU - Nguyen, Minh Tho

N1 - The work of PVN, NTS and MTN is funded by VinGroup Vietnam and supported by VinGroup Innovation Foundation (VinIF) under project code VinIF.2020.DA21. VGK acknowledges the support of the post-HF computational part of this work by the Supercomputer Center of Novosibirsk State University and Russian Science Foundation (project 22-13-00077). AF thanks G. Meijer for his continuing support and gratefully acknowledges the Stichting voor Fundamenteel Onderzoek der Materie (FOM) in providing beam time on FELIX, the skillful assistance of the FELIX staff now located at Radboud University Nijmegen, and the contributions of his co-authors of ref. 48 and 49 for obtaining the experimental data.

PY - 2023/3/29

Y1 - 2023/3/29

N2 - The geometry of the neutral Au18 gold cluster was probed by a combination of quantum chemical calculations and far-infrared multiple photon dissociation (FIR-MPD) spectroscopy of a Kr messenger complex. Two low-lying isomers are identified to potentially contribute to the experimental IR spectrum, both being derived from a star-like Au17 structure upon capping with one extra Au atom either inside (18_1) or outside (18_5) the star. In particular, the present detection of structure 18_1 by DFT computations where a golden cage encapsulates an endohedral Au atom, is intriguing as a stable core-shell isomer has, to our knowledge, never been found before for such small neutral gold clusters. DFT and local coupled-cluster (DLPNO and PNO-CCSD(T)) computations indicate that both Au18 isomers are close to each other, within ∼3 kcal mol-1, on the energy scale. Although the exact energy ordering is again method-dependent and remains, at present, inconclusive, the most striking spectral signatures of both isomers are related to vibrational modes localized at atoms capping the inner pentaprism sub-structure that result in prominent peaks centered at ∼80 cm-1, close to the most prominent experimental feature found at 78 cm-1. The calculated IR spectra of both core-shell and hollow isomers are very similar to each other and both agree comparably well with the experimental FIR-MPD spectra of the Au18Kr1,2 complexes.

AB - The geometry of the neutral Au18 gold cluster was probed by a combination of quantum chemical calculations and far-infrared multiple photon dissociation (FIR-MPD) spectroscopy of a Kr messenger complex. Two low-lying isomers are identified to potentially contribute to the experimental IR spectrum, both being derived from a star-like Au17 structure upon capping with one extra Au atom either inside (18_1) or outside (18_5) the star. In particular, the present detection of structure 18_1 by DFT computations where a golden cage encapsulates an endohedral Au atom, is intriguing as a stable core-shell isomer has, to our knowledge, never been found before for such small neutral gold clusters. DFT and local coupled-cluster (DLPNO and PNO-CCSD(T)) computations indicate that both Au18 isomers are close to each other, within ∼3 kcal mol-1, on the energy scale. Although the exact energy ordering is again method-dependent and remains, at present, inconclusive, the most striking spectral signatures of both isomers are related to vibrational modes localized at atoms capping the inner pentaprism sub-structure that result in prominent peaks centered at ∼80 cm-1, close to the most prominent experimental feature found at 78 cm-1. The calculated IR spectra of both core-shell and hollow isomers are very similar to each other and both agree comparably well with the experimental FIR-MPD spectra of the Au18Kr1,2 complexes.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85150871326&origin=inward&txGid=af41ea4441133de0ff75b6f315a9de2c

UR - https://www.mendeley.com/catalogue/7c965c98-c610-3f24-8d46-442e024ec3b2/

U2 - 10.1039/d2cp05422a

DO - 10.1039/d2cp05422a

M3 - Article

C2 - 36919716

VL - 25

SP - 9036

EP - 9042

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 13

ER -