Comparative study of tetramers built from Ia, IIa, IIIa, and IVa atoms

Koutecký, J.; Pacchioni, Gianfranco; Jeung, Gwang‐Hi; Haß, Ernst-Christoph

doi:10.1016/0039-6028(85)90237-7

Cited by 72 publications

(20 citation statements)

References 21 publications

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“…3͑a͔͒ in agreement with Koutecky et al, 43 Pettersson, 1 Bauschlicher and Pettersson 45 and Jones. 46 ReaxFF, on the other hand, finds a tetrahedron structure ͓Fig.…”

Section: A Heats Of Formation and Geometry Of Clusterssupporting

confidence: 90%

“…DFT calculation shows that the most stable form of Al 3 is an equilateral triangle, in agreement with the work of Pettersson et al 1 For Al 4 the planar rhombus ͑D 2h ͒ conformation is found to be more stable than the pyramidal form ͑C 3v ͒, in agreement with Koutecky et al 43 and Pettersson et al 1 In the case of Al 5 , Jug et al 44 found the pyramidal form to be the most stable, whereas Petterson et al 1 and Yang et al 9 found the planar ͑C 2v ͒ form to be more stable than the pyramidal form. The DFT calculations for Al 5 are consistent with the works of Yang et al 9 In addition, Pettersson et al 1 found that in the case of Al 6 the octahedron is the most stable form, whereas Upton 2 found a distorted octahedron to be the most stable.…”

Section: A Heats Of Formation and Geometry Of Clusterssupporting

confidence: 88%

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Predictions of melting, crystallization, and local atomic arrangements of aluminum clusters using a reactive force field

Ojwang

Santen

Kramer

et al. 2008

The Journal of Chemical Physics

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A parametrized reactive force field model for aluminum ReaxFF Al has been developed based on density functional theory ͑DFT͒ data. A comparison has been made between DFT and ReaxFF Al outputs to ascertain whether ReaxFF Al is properly parametrized and to check if the output of the latter has correlation with DFT results. Further checks include comparing the equations of state of condensed phases of Al as calculated from DFT and ReaxFF Al . There is a good match between the two results, again showing that ReaxFF Al is correctly parametrized as per the DFT input. Simulated annealing has been performed on aluminum clusters Al n using ReaxFF Al to find the stable isomers of the clusters. A plot of stability function versus cluster size shows the existence of highly stable clusters ͑magic clusters͒. Quantum mechanically these magic clusters arise due to the complete filling of the orbital shells. However, since force fields do not care about electrons but work on the assumption of validity of Born-Oppenheimer approximation, the magic clusters are therefore correlated with high structural symmetry. There is a rapid decline in surface energy contribution due to the triangulated nature of the surface atoms leading to higher coordination number. The bulk binding energy is computed to be 76.8 kcal/mol. This gives confidence in the suitability of ReaxFF for studying and understanding the underlying dynamics in aluminum clusters. In the quantification of the growth of cluster it is seen that as the size of the clusters increase there is preference for the coexistence of fcc/hcp orders at the expense of simple icosahedral ordering, although there is some contribution from distorted icosahedral ordering. It is found that even for aluminum clusters with 512 atoms distorted icosahedral ordering exists. For clusters with N Ն 256 atoms fcc ordering dominates, which implies that at this point we are already on the threshold of bulklike bonding.

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“…3͑a͔͒ in agreement with Koutecky et al, 43 Pettersson, 1 Bauschlicher and Pettersson 45 and Jones. 46 ReaxFF, on the other hand, finds a tetrahedron structure ͓Fig.…”

Section: A Heats Of Formation and Geometry Of Clusterssupporting

confidence: 90%

Section: A Heats Of Formation and Geometry Of Clusterssupporting

confidence: 88%

Predictions of melting, crystallization, and local atomic arrangements of aluminum clusters using a reactive force field

Ojwang

Santen

Kramer

et al. 2008

The Journal of Chemical Physics

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“…A summary is given in Table 10. The difference in stability of the most stable and least stable geometry for B 4 is 3.49 eV [56], whereas for A14 it is 0.48 eV (T~ for linear A14 is not available) and for Ga4 0.88 eV. It is thus easier to distort the 'metallic' cluster than the 'covalent' cluster.…”

Section: B Trimersmentioning

confidence: 91%

“…As a result first-row molecules favour [39] e Basis set B553, c%(3H~)=284 cm -1, O.~e(3Sg-')=340 cm -t g Ref. [56] h Angle is fixed at 120.0 ° i Ref. [39] an occupation of 1re, instead of 20-g.…”

Section: Ground States and Geometries Of Ga In Comparison With B Anmentioning

confidence: 99%

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Ab initio MRD-CI study of neutral and charged Ga2, Ga3 and Ga4 clusters and comparison with corresponding boron and aluminum clusters

Meier

Peyerimhoff

Grein

1990

Z Phys D - Atoms, Molecules and Clusters

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MRD-CI calculations were performed on Ga, Gaz, Ga3, Gag and on the corresponding positive and negative ions. In general, pseudopotentials were used, and 4s 4p/ 2s 2p basis sets with s and p diffuse functions and one or two d functions. For Ga2, all-electron calculations were also performed. For Ga~ -+), potential functions for ground and low-lying excited states are given. For c~,o(_+) geometries were optimized both in C2,, and D~h symmetry. The lowest state of Ga~-is found to be aS +, of Ga3 4A2, and of Ga; 1At(D3h). Ionization potentials and electron affinities of Ga3 were evaluated. Many towlying excited states of Ga~3 -+) were found. Rhombic (Dzh , including square D4h), tetrahedral (Ta), T-shaped (C2~) and linear structures (D~h) were investigated in the search for the lowest state of Ga4. A square-planar arrangement of the nuclei, with Re= 5.30 ao, was found to have the lowest energy. The other geometries lie about 0.5 eV higher. In Dzh symmetry, low-lying excited states of Ga4, as well as ground and excited states of Ga,~ and Gag were studied.Geometries, ionization potentials, electron affinities, atomization and fragmentation energies of Ga, are compared with corresponding data for B, and A1,. Typical changes in going from first-row to third-row atoms are observed.

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Nonlinear optical properties of the rhombic B4-cluster

Reis

Παπαδόπουλος

1999

J. Comput. Chem.

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The equilibrium geometry, energy, dipole polarizability, and second hyperpolarizability of the rhombic B4‐cluster with D2h symmetry are calculated by restricted (RHF) and unrestricted (UHF) Hartree–Fock theory; Møller–Plesset perturbation theory (MPn); coupled‐cluster theory with singles, doubles, and a perturbational treatment for connected triples [CCSD(T)]; Brueckner doubles with a perturbational treatment for connected triples [BD(T)]; and complete active space SCF (CASSCF) and restricted active space SCF (RASSCF) methods, using three different basis sets. The multireference methods show that excited state configurations contribute appreciably to the ground state wave function. Accordingly, the RHF method yields results that differ greatly from those of the correlated methods, even for the geometry. UHF gives more reliable geometries, but suffers from high spin contamination. The electric properties calculated at reasonably highly correlated levels are qualitatively comparable for both the single reference and multireference descriptions, although differences between CCSD(T) and BD(T) are larger than usually reported in the literature and properties calculated at the MPn (n=2, 3, 4) series show much damped oscillatory behavior, especially for the components along the long in‐plane axis. It is found that inclusion of f‐functions in the basis set do not have a large effect on the electric properties. ©1999 John Wiley & Sons, Inc. J Comput Chem 20: 679–687, 1999

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Comparative study of tetramers built from Ia, IIa, IIIa, and IVa atoms

Cited by 72 publications

References 21 publications

Predictions of melting, crystallization, and local atomic arrangements of aluminum clusters using a reactive force field

Predictions of melting, crystallization, and local atomic arrangements of aluminum clusters using a reactive force field

Ab initio MRD-CI study of neutral and charged Ga2, Ga3 and Ga4 clusters and comparison with corresponding boron and aluminum clusters

Nonlinear optical properties of the rhombic B4-cluster

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