Isomer identification and resolution in small gold clusters.

A variety of experimental techniques are used to resolve energetically close isomers of Au(7)(-) and Au(8)(-) by combining photoelectron spectroscopy and ab initio calculations. Two structurally distinct isomers are confirmed to exist in the cluster beam for both clusters. Populations of the different isomers in the cluster beam are tuned using Ar-tagging, O(2)-titration, and isoelectronic atom substitution by Cu and Ag. A new isomer structure is found for Au(7)(-), which consists of a triangular Au(6) unit with a dangling Au atom. Isomer-specific photoelectron spectra of Au(8)(-) are obtained from O(2)-titration experiment. The global minimum and low-lying structures of Au(7)(-), Au(8)(-), and MAu(n)(-) (n=6,7; M=Ag,Cu) are obtained through basin-hopping global minimum searches. The results demonstrate that the combination of well-designed photoelectron spectroscopy experiments (including Ar-tagging, O(2)-titration, and isoelectronic substitution) and ab initio calculation is not only powerful for obtaining the electronic and atomic structures of size-selected clusters, but also valuable in resolving structurally and energetically close isomers of nanoclusters.

[1]  S. Bulusu,et al.  Structural transition of gold nanoclusters: from the golden cage to the golden pyramid. , 2009, ACS nano.

[2]  B. Hammer,et al.  2D-3D transition for cationic and anionic gold clusters: a kinetic energy density functional study. , 2009, Journal of the American Chemical Society.

[3]  Lai‐Sheng Wang,et al.  Au10-: isomerism and structure-dependent O2 reactivity. , 2009, Physical chemistry chemical physics : PCCP.

[4]  K. J. Taylor,et al.  Ultraviolet photoelectron spectra of coinage metal clusters , 1992 .

[5]  Lai‐Sheng Wang,et al.  Detecting weak interactions between Au- and gas molecules: a photoelectron spectroscopic and ab initio study. , 2009, Journal of the American Chemical Society.

[6]  P. Pyykkö.  Structural properties: magic nanoclusters of gold. , 2007, Nature nanotechnology.

[7]  Lai‐Sheng Wang,et al.  TEMPERATURE EFFFECTS IN ANION PHOTOELECTRON SPECTROSCOPY OF METAL CLUSTERS , 2000 .

[8]  Hannu Häkkinen,et al.  Bonding in Cu, Ag, and Au clusters: relativistic effects, trends, and surprises. , 2002, Physical review letters.

[9]  David E. Bernholdt,et al.  High performance computational chemistry: An overview of NWChem a distributed parallel application , 2000 .

[10]  S. Yoo,et al.  Motif transition in growth patterns of small to medium-sized silicon clusters. , 2005, Angewandte Chemie.

[11]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[12]  Hannu Häkkinen,et al.  On the Electronic and Atomic Structures of Small AuN- (N = 4−14) Clusters: A Photoelectron Spectroscopy and Density-Functional Study , 2003 .

[13]  Pekka Pyykkö,et al.  Theoretical chemistry of gold. , 2004, Angewandte Chemie.

[14]  Britta Redlich,et al.  Structures of Neutral Au7, Au19, and Au20 Clusters in the Gas Phase , 2008, Science.

[15]  S. Bulusu,et al.  Doping golden buckyballs:Cu@Au16- and Cu@Au17- cluster anions. , 2007, Angewandte Chemie.

[16]  Uzi Landman,et al.  Structural evolution of Au nanoclusters: From planar to cage to tubular motifs , 2006 .

[17]  D. Zubarev,et al.  Deciphering chemical bonding in golden cages. , 2009, The journal of physical chemistry. A.

[18]  M. Knickelbein,et al.  Metal cluster—rare gas van der Waals complexes: NbnArm and FenKrm , 1991 .

[19]  H. Scheraga,et al.  Global optimization of clusters, crystals, and biomolecules. , 1999, Science.

[20]  Leiming Wang,et al.  Tuning the electronic properties of the golden buckyball by endohedral doping: M@Au16(-) (M = Ag,Zn,In). , 2009, The Journal of chemical physics.

[21]  Jun Li,et al.  Au20: A Tetrahedral Cluster , 2003, Science.

[22]  D. Truhlar,et al.  Validation study of the ability of density functionals to predict the planar-to-three-dimensional structural transition in anionic gold clusters. , 2009, The Journal of chemical physics.

[23]  Photoelectron spectra of aluminum cluster anions: Temperature effects and ab initio simulations , 1999, physics/9909058.

[24]  Mark S Gordon,et al.  Isomers of Au8. , 2007, The Journal of chemical physics.

[25]  G. Hutchings,et al.  Identification of Active Gold Nanoclusters on Iron Oxide Supports for CO Oxidation , 2008, Science.

[26]  Pekka Pyykkö,et al.  Theoretical chemistry of gold. II , 2005 .

[27]  Pekka Pyykkö,et al.  Theoretical chemistry of gold. III. , 2008, Chemical Society reviews.

[28]  M. Kappes,et al.  Electronic photodissociation spectroscopy of Aun- x Xe (n = 7-11) versus time-dependent density functional theory prediction. , 2004, The Journal of chemical physics.

[29]  M. Musiał,et al.  Where does the planar-to-nonplanar turnover occur in small gold clusters? , 2005, Journal of the American Chemical Society.

[30]  Mikael P. Johansson,et al.  2D-3D transition of gold cluster anions resolved , 2008 .

[31]  Lai‐Sheng Wang,et al.  Photoelectron spectroscopy of size‐selected transition metal clusters: Fe−n, n=3–24 , 1995 .

[32]  M. Knickelbein,et al.  Isomers of niobium clusters: direct spectroscopic evidence , 1990 .

[33]  Masatake Haruta,et al.  Size- and support-dependency in the catalysis of gold , 1997 .

[34]  H. Häkkinen,et al.  Atomic and electronic structure of gold clusters: understanding flakes, cages and superatoms from simple concepts. , 2008, Chemical Society reviews.

[35]  Pekka Pyykkö,et al.  Relativistic effects in structural chemistry , 1988 .

[36]  P. Weis.  Structure determination of gaseous metal and semi-metal cluster ions by ion mobility spectrometry , 2005 .

[37]  M. Walter,et al.  A hollow tetrahedral cage of hexadecagold dianion provides a robust backbone for a tuneable sub-nanometer oxidation and reduction agent via endohedral doping. , 2006, Physical chemistry chemical physics : PCCP.

[38]  Uzi Landman,et al.  Materials by numbers: computations as tools of discovery. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[39]  J. Behler,et al.  Structure determination of isolated metal clusters via far-infrared spectroscopy. , 2004, Physical review letters.

[40]  M. Moseler,et al.  Liquid-liquid phase coexistence in gold clusters: 2D or not 2D? , 2007, Physical review letters.

[41]  Wei Huang,et al.  Probing the 2D to 3D structural transition in gold cluster anions using argon tagging. , 2009, Physical review letters.

[42]  Xiao Cheng Zeng,et al.  Evidence of hollow golden cages. , 2006, Proceedings of the National Academy of Sciences of the United States of America.

[43]  Christoph R. Jacob,et al.  The structures of small gold cluster anions as determined by a combination of ion mobility measurements and density functional calculations , 2002 .

[44]  Kwang S. Kim,et al.  Spatial structure of Au8: Importance of basis set completeness and geometry relaxation. , 2006, The journal of physical chemistry. B.

[45]  Christian Neiss,et al.  Structure determination of gold clusters by trapped ion electron diffraction: Au(14)(-)-Au(19)(-). , 2009, Physical chemistry chemical physics : PCCP.