# Hung Tan PhamKU Leuven | ku leuven · Department of Chemistry

Hung Tan Pham

BSc

## About

44

Publications

6,544

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682

Citations

Citations since 2017

Introduction

Additional affiliations

July 2015 - present

June 2015 - present

May 2012 - January 2016

## Publications

Publications (44)

The Au17 gold cluster was experimentally produced in the gas phase and characterized by its vibrational spectrum recorded using far-IR multiple photon dissociation (FIR-MPD) of Au17Kr. DFT and coupled-cluster theory PNO-LCCSD(T)-F12 computations reveal that, at odds with most previous reports, Au17 prefers two star-like forms derived from a pentapr...

Geometries of doubly transition metal doped silicon clusters M2Sin, M2 = Mo2, Nb2, Ta2, W2, NbMo, TaW were determined by DFT computations. Geometries of M2Sin in the range from 11 to 18 Si atoms change from a tubular shape to a cage and then a fused cage. The M2Si18 sizes present us with a novel structural motif, the fused cage, for silicon cluster...

The NbAl8H8+ cluster was formed in a molecular beam and characterized by mass spectrometry and infrared spectroscopy. Density functional theory calculations show the lowest-energy isomer is a high symmetry singlet with the Nb atom placed at the center of a distorted hexagonal Al ring and coordinated by two AlH moieties, therefore exhibiting octacoo...

The first trefoil leaf-shaped cluster, a novel structural motif, was discovered by quantum chemical computations using density functional theory methods for both binary M3@E20 silicon and germanium clusters in which a metallic M3 cycle is encapsulated within a D3h Si20 or Ge20 cage. The triatomic transition metal Fe3, Ru3 and Os3 cycles exhibit a s...

A pentagonal hetero-prismatic structural motif was found for singly transition metal doped M@Ge5E5⁺ clusters, where the transition metal atom is located at the centre of a (5/5) Ge5E5 prism in which Ge is mixed with either P or As atoms. Structural characterization indicates that each (5/5) Ge5E5 prism is established by joining of two Ge3E2 and Ge2...

Structural transformation is a unique characteristic of the atomic clusters but it turns out very different from cluster to cluster. This theoretical study proves that the isomeric transformation between hexagonal prism and hexagonal anti-prism is found for the doubly doped Cr2Ge12 cluster but not for singly doped CrGe12 cluster. We confirm that th...

Some boron doped germanium clusters BxGe12q with x = 1, 2, 3 and 4 and q = 0, 1 were designed as stabilized double ring tubes. While the B2Ge12 constitutes the smallest deltahedral germanium cluster, both B3Ge12+ and B4Ge12 clusters present us, for the first time, with an endohedral tubular motif in which either the B3 or the B4 cycle is encapsulat...

In the present theoretical study using DFT computations, we successfully designed a series of boron clusters possessing a teetotum shape stabilized upon metal doping. The resulting M2B18 teetotum geometry emerges as a general structural motif for the B18 boron cluster doped by either two 4d and 5d transition metal atoms. Doping of two different met...

A teetotum form is found as the global equilibrium structure of V 2 B 7+/0/− clusters. Formation of a bimetallic configuration and aromaticity are found to be dominant factors stabilizing the doped V 2 B 7+/0/− teetotum structures. Magnetic ring current maps indicate the V 2 B 7⁺ cation as doubly aromatic. Exploration on the interactions of one and...

A systematic investigation on structure, relative stabilities, dissociation behavior and bonding of the singly and doubly Ni doped boron clusters BnNim with n = 2 −22 and m = 1 – 2, was carried out using density functional theory calculations. Calculated results indicate that for n < 14, the BnNim structures are generally formed by capping Ni atom(...

(Abstract) The lowest-lying isomer of the B50 boron cluster is confirmed to have a quasi-planar shape with two hexagonal holes. By applying the topological (leap-frog) dual operation followed by a boron capping, we demonstrated that such a quasi-planar structure actually comes from the smallest elongated B102-, and its high thermodynamic stability...

Binary BnAln clusters (n = 1–7) were investigated using both DFT/TPSSh and G4 calculations. B and Al atoms do not mix together but prefer to be assembled in two separated but interacting Bn and Aln components. Large electron donation from Al to B atoms induces a donor-acceptor stabilization. Planar B3Al3 is a σ aromatic compound. B4Al4 exhibits two...

(Abstract) Geometries, bonding and abilities for CO2 capture of the doubly rhodium-doped boron cluster Rh2B18 are presented. DFT calculations using the TPSSh functional show that the doubly doped Rh2B18 is stable in a high symmetry shape (D9d) in which two Rh dopants are vertically and oppositely coordinated to nonagonal faces of a (2 x 9) double r...

We investigated the geometry, stability and aromaticity of a series of singly and doubly titanium-doped boron clusters. Ti dopants bring in planar cyclic form with a nine-membered boron ring B9- and B93-, and C, N isoelectronic derivatives where perfectly planar B6N3, B6CN2, B6C2N and B6C3 hetero-rings are coordinated with one and two Ti atoms. The...

Remarkably strong effects of the aromatic B3 cycle in stabilizing tubular silicon clusters were observed for the first time. The doped cluster B3@Si12+ presents a novel structural motif for silicon clusters in which a B3 cycle is encapsulated into a (6 x 2) Si12 prism giving raise to a high symmetry stable tubular structure (D3h). A large amount of...

(Abstract) The aromatic character of some small planar metallic clusters was revisited with an emphasis on their σ electrons. In contrast to previous reports, our approach based on magnetic ring current as an indicator for aromaticity points out that the σ electron delocalization in molecules behaves as an important contributor to their thermodynam...

A B3N3Si8 cage is formed upon substitution of Si sites of rhombus faces of the pure Si14 cluster by B and N atoms. Doping by the ion Mn+ leads to the hetero-silicon fullerene B3N3Si8Mn+ which comprises three rhombus BNBN, Si3B and Si3N, and four pentagons (two Si2B2N and two Si2BN2). Hetero-atoms form polarized Si-N and Si-B bonds as indicated by e...

An investigation on structure, stability, and magnetic properties of singly doped Au19M (M=Cr, Mn, and Fe) clusters is carried out by means of density functional theory calculations. The studied clusters prefer forming magnetic versions of the unique tetrahedral Au20. Stable sextet Au19Cr is identified as the least reactive species and can be quali...

(Abstract) Recently, metallic hetero-fullerenes were experimentally prepared from mixed Ge-As clusters and heavier elements of groups 14 and 15. We found that shape of these hetero-fullerenes doped by transition metal appears to be a general structural motif for both silicon and germanium clusters when mixing with phosphorus and arsenic atoms. Stru...

This chapter consists of a review on the geometric, electronic structure and chemical bonding in a number of small boron clusters doped by two transition metal elements. First-row transition metals introduce not only new class of boron clusters but also particular growth patterns. In the bimetallic cyclic motif, the two metals are vertically coordi...

The geometrical evolution, electronic structure and thermodynamic stability of a series of singly-doped SinP and doubly-doped SinP2 silicon clusters with n = 1-10, in the neutral, cationic and anionic states were systematically investigated using DFT computations. The global minimum structures were identified using different search approaches. The...

Geometries and electronic properties related to the ground state stabilities of several Si12M2 clusters (M: second-row (Nb and Mo) and third-row (Ta and W) transition metals, and their mixed bimetallic clusters M2: NbMo and TaW) were explored using density functional theory (DFT) computations. The computed results show that two different structural...

Geometry, chemical bonding and aromatic feature of a series of small silver clusters doped by an Sc atom (ScAgn with n = 1-7) were investigated by mean of DFT calculations. A planar shape is found for ScAgn including n from 4 to 7. The growth mechanism is established for the formation of the hexagonal and heptagonal metallic cycles following increa...

A systematic investigation on structure, dissociation behavior, chemical bonding, and magnetic property of Cr-doped Cun clusters (n = 9-16) is carried out using the mean of density functional theory calculations. It is found that CrCu12 is a crucial size, preferring an icosahedral Cu12 cage with the central Cr dopant. Smaller cluster sizes appear a...

A theoretical investigation of the geometry, stability and aromaticity of boron clusters doped by two Sc and Ti atoms was carried out using DFT calculations. The Sc and Ti atoms form the bimetallic boron cycles not only with the eight-membered ring B 8 2À but also with the isoelectronic species B 7 N and B 6 C 2 rings yielding the planar B 8 2À , B...

A theoretical investigation of the geometry, stability and aromaticity of boron clusters doped by two Sc and Ti atoms was carried out using DFT calculations. The Sc and Ti atoms form the bimetallic boron cycles not only with the eight-membered ring B82- but also with the isoelectronic species B7N and B6C2 rings yielding the planar B82-, B7N and B6C...

The planarity of small boron-based clusters is the result of an interplay between geometry, electron delocalization, covalent bonding and stability. These compounds contain two different bonding patterns involving both σ and π delocalized bonds, and up to now, their aromaticity has been assigned mainly using the classical (4N + 2) electron count fo...

We study CoxCryOm+ (x + y = 2, 3 and 1 ≤ m ≤ 4) clusters by means of density-functional-theory calculations. It is found that the clusters grow preferentially through maximizing the number of metal-oxygen bonds with a favor on Cr sites. The size- and composition-dependent magnetic behavior is discussed in relation with the local atomic magnetic mom...

The smallest triple ring tubular silicon cluster Mn2@Si15 is reported for the first time. Theoretical structural identification shows that the Mn2@Si15 tubular structure whose triple ring is composed by three five-membered Si rings in anti-prism motif, is stable in high symmetry (D5h) and singlet ground state (1A1’). The dimer Mn2 is placed inside...

Using density functional theory with the TPSSh functional and the 6-311+G(d) basis set, we extensively searched for the global minima of two metallic atoms doped boron clusters B6M2, B7M2, B12M2 and B14M2 with transition metal element M being Co and Fe. Structural identifications reveal that B7Co2, B7Fe2 and B7CoFe clusters have global minima in a...

The smallest triple ring tubular silicon cluster Mn2@Si15 is reported for the first time. Theoretical structural identification shows that the Mn2@Si15 tubular structure whose triple ring is composed by three five-membered Si rings in anti-prism motif, is stable in high symmetry (D5h) and singlet ground state (1A1’). The dimer Mn2 is placed inside...

The smallest triple ring tubular silicon cluster Mn2@Si15 is reported for the first time. Theoretical structural identification shows that the Mn2@Si15 tubular structure whose triple ring is composed by three five-membered Si rings in anti-prism motif, is stable in high symmetry (D5h) and singlet ground state (1A1’). The dimer Mn2 is placed inside...

We revisit the singlet-triplet energy gap (ΔEST ) 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...

Stabilized fullerene and tubular forms can be produced in boron clusters Bn in small sizes from n ~ 14 upon doping by transition metal atoms. B14Fe and B16Fe are stable tubes whereas B18Fe and B¬20Fe are stable fullerenes. The magnetic moment in B18Fe is completely quenched. Their formation and stability suggest the use of dopants to induce differe...

ABSTRACT: We analyzed the chemical bonding phenomena of the boron B2n
tubes (n = 10−14). The B2n tubes represent stable hollow cylinders each having a
double ring (DR) among pure boron clusters. The shapes of the molecular
orbitals of a B2n DR can be predicted by the eigenstates of a simple model of a
particle on a hollow cylinder, which shows both...

We determined the geometries and chemical bonding phenomena of the B27 system in its dicationic, cationic, neutral, anionic and dianionic states using DFT computations. In both cationic and neutral states, the triple ring tubular forms correspond to the lowest-energy isomers, especially in B27(+). The cation B27(+) represents the first stable hollo...

We revisited the aromaticity of silicon tetramer Si4, Si42+ and isoelectronic four-membered rings without
and with a planar tetracoordinate carbon dopant (Si4C2+). Electron localizability indicators and magnetic
ring currents were used to probe bonding patterns. Comparison with Al42�, Si2Al2, Al4C2� and Si2Al2C was performed. The 14 (Si42+), 16 (Si...

The B30 boron cluster has a bowl rather than a double-ring or a triple-ring tubular structure. This bowl isomer exhibits disk-aromaticity similar to that found for B20(2-) and B19(-) clusters. We confirmed that the concept of disk-aromaticity can be applied to both planar and non-planar systems.

## Projects

Projects (2)

Determination of structures, molecular and magnetic properties of B and Si clusters doped by different types of elements.