Ab initio crystal orbital studies on linear chains of H atoms

Kertész, Miklós; Koller, J.; Ažman, A.

doi:10.1007/bf00558027

Cited by 37 publications

(11 citation statements)

References 8 publications

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“…Despite the fact that equi-spaced infinite H chain in 3D suffers from a Peierls instability, 108 this system has attracted considerable interest due to its strong correlation character and metal-insulator transition. We have expanded the HF orbital in the unit cell (x ∈ [−R/2, R/2]) as a linear combination of K even polynomials (3).…”

Section: Hydrogen Nanowirementioning

confidence: 99%

Chemistry in one dimension

Loos

Ball

Gill

2015

Phys. Chem. Chem. Phys.

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We report benchmark results for one-dimensional (1D) atomic and molecular systems interacting via the Coulomb operator |x| −1 . Using various wavefunction-type approaches, such as Hartree-Fock theory, second-and third-order Møller-Plesset perturbation theory and explicitly correlated calculations, we study the ground state of atoms with up to ten electrons as well as small diatomic and triatomic molecules containing up to two electrons. A detailed analysis of the 1D helium-like ions is given and the expression of the high-density correlation energy is reported. We report the total energies, ionization energies, electron affinities and other interesting properties of the many-electron 1D atoms and, based on these results, we construct the 1D analog of Mendeleev's periodic table. We find that the 1D periodic table contains only two groups: the alkali metals and the noble gases. We also calculate the dissociation curves of various 1D diatomics and study the chemical bond in H + 2 , HeH 2+ , He 3+ 2 , H 2 , HeH + and He 2+ 2 . We find that, unlike their 3D counterparts, 1D molecules are primarily bound by one-electron bonds. Finally, we study the chemistry of H + 3 and we discuss the stability of the 1D polymer resulting from an infinite chain of hydrogen atoms.

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Section: Hydrogen Nanowirementioning

confidence: 99%

Chemistry in one dimension

Loos

Ball

Gill

2015

Phys. Chem. Chem. Phys.

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“…This distance has been found [6] tic quantities is worse. While the total energy changes less thaa 0.0005 a.u.…”

Section: Convergency With Respect To the Number Of Neighboursmentioning

confidence: 82%

“…In our ab initio treatment of the equidistant H chains [6] and polyene [8] besides the symmetrie (metallic) solution also broken-symmetry (insular-M. ~ERTs ing) solutions with a lower energy have been found indicating the instability of the equidistant nuclear configurations.…”

Section: Discussionmentioning

confidence: 98%

“…and the summation over i in (5) extends over all the occupied orbital indices. Starting from the above UHF MO equations one can simply get the UHF CO equations by substituting the Bloch form (2) of the orbitals into (4)-- (6). Then the practically manageable LCAO form can be obtained formally by multiplying from left by Z*(rl) and integrating over d3rl.…”

Section: Methods Of Calculationmentioning

confidence: 99%

“…We have applied our BLOCH programs to several systems: chains of hydrogen atoms with both metallic and molecular crystal type models [6,10]; hydrogen bonded molecular chains, as hydrogen fluoride [5] and hydrogen cyanide [7]; polyene [8]; polysulfur-nit¡ chain [9]. The energy band structutes as well as other results can be found in these papers.…”

Section: Some Characteristics Of the Computer Programmentioning

confidence: 99%

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On the AB initio crystal orbital method

Kertész

1976

Acta Physica

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A new computer realization of the LCAO Hartree--Fock crystal orbital method using contracted Gaussian orbitals is reported. AH integrals over the atomie orbitals are ealculated explieitly within a finite interaction range. No approximation with respeet to exchange is used. The spin-unrestricted Hartree--Fock-type crystal orbital formalism has been programmed, too. Both programs are limited to quasi one-dimensional systems at present, provide nevertheless a useful tool for the theoretical investigation of the eleetronic strueture of simple polymers and one-dimensional models of solids. Basic information on both programs is documented.Some numerieal aspeets, especially the convergency properties of the methods with respect to the number of grid points in the Brillouin zone, the shape of the Fermi surfaee in the special case of partly filled bands, the starting density matrices in the self-eonsistent field iteration procedure and the size of the finite interactiort range taken into account are diseussed. The specific problem of the starting density matrices in the unrestricted HF case are also dealt with. Finally comparison is made with semi-empirical ealculations. lntroductionThe linear eombination of atomic orbitals (LCAO) Hartree--Fock (HF) molecular orbital (MO) as well as crystal orbital (CO) methods appear nowadays well established calculational tools for the investigation of the electronic structure of molecules and solids, respectively. A number of physical observables can be estimated well even from approximate HF wave functions (especially one-particle properties) while others await correlation corrections. Thus it is easy to understand that a large effort has been devoted to the calculation of the LCAO HF CO-s (and energy bands) of many systems. It Ÿ not the aim of the present work to review this s we refcr to two review papers only, eovering part of the actual caleulations [1]. From the methodological point of view these calculations are either semi-empirical using usually one of the integral approximation schemes of the approximate quantum chemical MO methods of are of nonempirical nature. The lattcr are often termed ab initio but use in fact in the majority of cases some kind of approximation scheme [2] for the integrals over the atomic orbitals (AO-s) entering in the LCAO CO formalista. In this paper we shall use the term ab initio (in close *

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