Ab-initio calculations of the covalent-ionic curve crossing in LiF

Botter, B.J.; Kooter, J.A.; Mulder, J. J. C.

doi:10.1016/0009-2614(75)85767-8

Cited by 29 publications

(14 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As already pointed out in the introduction the LiF molecule has been frequently studied in the literature by various groups [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. The ionic and covalent states of 1 Σ + symmetry assemble an avoided crossing for an inter-atomic distance of ∼11.5 a.u.…”

Section: Avoided Crossing Of Lithium Fluoridementioning

confidence: 99%

See 1 more Smart Citation

Multi-reference coupled-cluster study of the ionic-neutral curve crossing LiF

Hanrath

2008

Molecular Physics

View full text Add to dashboard Cite

HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Multi-reference coupled-cluster study of the ionic-neutral curve crossing LiFMichael Hanrath To cite this version:Michael Hanrath. Multi-reference coupled-cluster study of the ionic-neutral curve crossing LiF.

show abstract

Section: Avoided Crossing Of Lithium Fluoridementioning

confidence: 99%

“…Therefore, it has been frequently used in the literature as a benchmark system. Initially there were MCSCF and CI calculations of Kahn et al [1], Botter et al [2], and Werner et al [3]. Later Spiegelmann et al [4,5] applied effective Hamiltonian techniques.…”

Section: Introductionmentioning

confidence: 99%

Multi-reference coupled-cluster study of the ionic-neutral curve crossing LiF

Hanrath

2008

Molecular Physics

View full text Add to dashboard Cite

show abstract

“…Previous calculations on LiF [15,16] have shown that there is appreciable ionic-covalent mixing even at a separation of 11 a 0 which is the ionic-covalent diabatic crossing point. This is evidence that the charge-transfer contribution to the energy falls off slowly with distance even though it is formally an exponentially decaying term.…”

Section: Calculationsmentioning

confidence: 97%

Many-body contributions to the intermolecular potential in alkali halide crystals and clusters

1981

View full text Add to dashboard Cite

SCFMO calculations have been made on lithium fluoride clusters both within the crystal and as isolated species. Calculations have been made with different bases in order to separate exchange, charge-transfer and induction energies. Calculations confirm the conclusion from perturbation theory that charge-transfer is an important contribution to three-body energies and gives a small four-body energy. The three-body energies in the crystal environment are much smaller than for the isolated clusters. I. INTRODUCTIONThe considerable interest in the static and dynamic properties of ionic crystals, both perfect and defective lattices, and ionic melts, provides a continuing incentive to obtain accurate interionic potential functions. There has indeed been no lack of effort on this front; the first alkali halide potentials which gave a good fit to the lattice energy were obtained by Huggins and Mayer in 1933 [1].The total potential for a finite cluster of ions can be written as a many-body expansion. The first term will be the sum of pair potentials, the second we refer to as the three-body term, etc. The pair potentials contain the Coulomb energy, which is dominant at large distances and the exchange energy which provides the short range repulsion. There will be other smaller terms, some long range and some short, such as dispersion, induction and charge transfer, whose relative importance depends on the internuclear separation. There are however problems relating to whether these energies make separate and additive contributions to the two-body energy [2]. For polar molecules and particularly for ions it has generally been considered that the inductive energies are the most important contribution to the higher n-body terms. These energies are associated with the polarization of one atom or molecule in the total electric field arising from its neighbours. As the component fields must be combined vectorially the polarization depends on the relative positions of the neighbours.

show abstract

“…The latter methods focus on dynamic correlation and are mandatory for achieving quantitative agreement with experiment. A frequently studied test system for the quantitative calculation of electron correlation effects in molecules is the ionic-neutral avoided crossing in the potential curves of alkaline halogenides, in particular of LiF [4,5,6,7,8,9,10,11,12]. The goal of these benchmark studies is the development of a computational protocol which provides a globally accurate description of the system even though the wave functions change dramatically transversing the avoided crossing.…”

Section: Introductionmentioning

confidence: 99%

“…This system has been subject of various earlier theoretical studies [4,5,6]. Kahn, Hay and Shavitt [4] calculated the four lowest 1 Σ + states using the configurationinteraction (CI) methods.…”

Section: Introductionmentioning

confidence: 99%

QC-DMRG study of the ionic-neutral curve crossing of LiF

Legeza¹,

Röder²,

Heß³

2003

Mol. Phys.

135

153

View full text Add to dashboard Cite

We have studied the ionic-neutral curve crossing between the two lowest 1 Σ + states of LiF in order to demonstrate the efficiency of the quantum chemistry version of the density matrix renormalization group method (QC-DMRG). We show that QC-DMRG is capable to calculate the ground and several low-lying excited state energies within the error margin set up in advance of the calculation, while with standard quantum chemical methods it is difficult to obtain a good approximation to Full CI property values at the point of the avoided crossing. We have calculated the dipole moment as a function of bond length, which in fact provides a smooth and continuous curve even close to the avoided crossing, in contrast to other standard numerical treatments.

show abstract

Ab-initio calculations of the covalent-ionic curve crossing in LiF

Cited by 29 publications

References 4 publications

Multi-reference coupled-cluster study of the ionic-neutral curve crossing LiF

Multi-reference coupled-cluster study of the ionic-neutral curve crossing LiF

Many-body contributions to the intermolecular potential in alkali halide crystals and clusters

QC-DMRG study of the ionic-neutral curve crossing of LiF

Contact Info

Product

Resources

About