Xiao-Jiao Deng

Thermal Methane Activation by La6O10− Cluster Anions

The first example of a metal oxide cluster anion, La6 O10 (-) that can activate methane under ambient conditions is reported. This reaction is facilitated by the oxygen-centered radical (O(-⋅) ) and follows the hydrogen atom transfer mechanism. The La6 O10 (-) has a high vertical electron detachment energy (VDE=4.06 eV) and a high symmetry (C4v ).

Structural and Magnetic Properties of CoGen− (n=2–11) Clusters: Photoelectron Spectroscopy and Density Functional Calculations

A series of cobalt-doped germanium clusters, CoGe(n)(-/0) (n=2-11), are investigated by using anion photoelectron spectroscopy combined with density functional theory calculations. For both anionic and neutral CoGe(n) (n=2-11) clusters, the critical size of the transition from exo- to endohedral structures is n=9. Natural population analysis shows that there is electron transfer from the Ge(n) framework to the Co atom at n=7-11 for both anionic and neutral CoGe(n) clusters. The magnetic moments of the anionic and neutral CoGe(n) clusters decrease to the lowest values at n=10 and 11. The transfer of electrons from the Gen framework to the Co atom and the minimization of the magnetic moments are related to the evolution of CoGe(n) structures from exo- to endohedral.

Smallest fullerene-like silicon cage stabilized by a V2 unit

We conducted a combined anion photoelectron spectroscopy and density functional theory study on V2Si20 cluster. Our results show that the V2Si20 cluster has an elongated dodecahedron cage structure with a V2 unit encapsulated inside the cage. It is the smallest fullerene-like silicon cage and can be used as building block to make cluster-assembled materials, such as pearl-chain style nanowires.

Photoelectron spectroscopy and density functional calculations of AgSin− (n = 3–12) clusters

We investigated the structural evolution and electronic properties of AgSi(n)(-) (n = 3-12) clusters using anion photoelectron spectroscopy and density functional theory calculations. The vertical detachment energies and adiabatic detachment energies of AgSi(n)(-) (n = 3-12) clusters were estimated from their photoelectron spectra. The structures of the AgSi(n)(-) (n = 3-12) clusters were tentatively assigned based on the comparison of theoretical calculations and experimental measurements. The studies show that the structures of AgSi(n)(-) (n = 3-12) clusters are dominated by exohedral structures with the Ag atom occupying the low coordinated sites. No endohedral structure has been found for AgSi(n)(-) clusters with n ≤ 12.

Structural and bonding properties of small TiGen− (n = 2–6) clusters: photoelectron spectroscopy and density functional calculations

A number of small TiGen− (n = 2–6) clusters were investigated using anion photoelectron spectroscopy and density functional theory calculations. Their structures were determined by comparison of the theoretical vertical detachment energies and simulated spectra of the low-lying isomers with the experimental results. The most stable structure of TiGen− (n = 2–6) clusters can be considered as a Ti atom substituting one of the Ge atoms in the corresponding Gen+1 cluster or a Ti atom capping a Gen cluster. The HOMOs of TiGen− (n = 2–6) clusters are mainly localized on the Ti atom and the Ge atoms interacting directly with the Ti atom.

Photoelectron spectroscopy and ab initio calculations of small SinSm− (n = 1,2; m = 1–4) clusters

Binary cluster anions composed of silicon and sulfur elements, SinSm(-) (n = 1,2; m = 1-4), were investigated by using photoelectron spectroscopy and ab initio calculations. The vertical detachment energies and the adiabatic detachment energies of these clusters were obtained from their photoelectron spectra. The electron affinity of SiS molecule is determined to be 0.477 ± 0.040 eV. The results show that the most stable structures of the anionic and neutral SinSm (n = 1,2; m = 1-4) clusters prefer to adopt planar configurations except that the structures of Si2S4(-) and Si2S2 are slightly bent.

Structural and magnetic properties of FeGen−/0 (n = 3-12) clusters: Mass-selected anion photoelectron spectroscopy and density functional theory calculations

The structural, electronic, and magnetic properties of FeGen-/0 (n = 3-12) clusters were investigated by using anion photoelectron spectroscopy in combination with density functional theory calculations. For both anionic and neutral FeGen (n = 3-12) clusters with n ≤ 7, the dominant structures are exohedral. The FeGe8-/0 clusters have half-encapsulated boat-shaped structures, and the opening of the boat-shaped structure is gradually covered by the additional Ge atoms to form Gen cage from n = 9 to 11. The structures of FeGe10-/0 can be viewed as two Ge atoms symmetrically capping the opening of the boat-shaped structure of FeGe8, and those of FeGe12-/0 are distorted hexagonal prisms with the Fe atom at the center. Natural population analysis shows that there is an electron transfer from the Ge atoms to the Fe atom at n = 8-12. The total magnetic moment of FeGen-/0 and local magnetic moment of the Fe atom have not been quenched.

Photoelectron spectroscopy and density functional calculations of C(n)S(m)(-) (n = 2-7; m = 1, 2) clusters.

CnSm(-) (n = 2-7; m = 1, 2) clusters were investigated by using photoelectron spectroscopy combined with density functional theory calculations. We found that the vertical detachment energies of both CnS(-) and CnS2(-) (n = 2-7) clusters exhibit a strong odd-even alternation with an increasing number of carbon atoms: the VDEs of even-n clusters are higher than those of adjacent odd-n clusters. The most stable structures of the anionic and neutral CnS (n = 2-7) clusters are linear with the S atom locating at one end of the carbon chain except that the structure of C3S(-) is slightly bent. The ground state isomers of the anionic and neutral CnS2 (n = 2-7) clusters are all linear structures with two S atoms locating at two ends of the carbon chain. The electron affinities of the neutral CnS (n = 2, 4-7) and CnS2 (n = 2-7) clusters are determined based on the experimental adiabatic detachment energies of the corresponding anion species, because the most stable structures of the neutral clusters are similar to those of the corresponding anions.

Structural and electronic properties of HCnS− (n = 4–11): anion photoelectron spectroscopy and density functional calculations

We investigated the HCnS− (n = 4–11) clusters using anion photoelectron spectroscopy and density functional theory calculations. The partially resolved vibrational spectra of the HCnS− (n = 4–11) clusters are obtained. We found that the vertical detachment energies of the HCnS− (n = 4–11) clusters display an obvious parity effect with increasing number of carbon atoms: the vertical detachment energies of the even-numbered HCnS− are higher than their neighboring odd-numbered counterparts; the spectral features of the even-numbered HCnS− are much sharper than those of their odd-numbered counterparts. The ground-state structures of the anionic and neutral HCnS (n = 4–11) clusters are linear with the H and S atoms locating at two ends of the carbon chain. The electron affinities of the neutral HCnS (n = 4–11) clusters are determined based on the transitions from the ground states of HCnS− anions to the electronic ground states of HCnS neutral species.