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

Hanrath, Michael

doi:10.1080/00268970802395120

Cited by 20 publications

(18 citation statements)

References 56 publications

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“…There are similar methodological problems in the case of the dissociation of ionic molecules, e.g. LiF, where deficiencies in RHF or DFT calculations lead to (partially) charged atoms at large separation, while a correct treatment does always yield neutral open-shell atoms after the crossover in the total energies of the neutral and ionic states 44,45 .…”

Section: Discussionmentioning

confidence: 99%

Multideterminant assessment of mean-field methods for the description of electron transfer in the weak-coupling regime

2009

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Multideterminant calculations have been performed on model systems to emphasize the role of many-body effects in the general description of charge quantization experiments. We show numerically and derive analytically that a closed-shell ansatz, the usual ingredient of mean-field methods, does not properly describe the step-like electron transfer characteristic in weakly coupled systems. With the multideterminant results as a benchmark, we have evaluated the performance of common ab initio mean field techniques, such as Hartree Fock (HF) and Density Functional Theory (DFT) with local and hybrid exchange correlation functionals, with a special focus on spin-polarization effects. For HF and hybrid DFT, a qualitatively correct open-shell solution with distinct steps in the electron transfer behaviour can be obtained with a spin-unrestricted (i.e., spin-polarized) ansatz though this solution differs quantitatively from the multideterminant reference. We also discuss the relationship between the electronic eigenvalue gap and the onset of charge transfer for both HF and DFT and relate our findings to recently proposed practical schemes for calculating the addition energies in the Coulomb blockade regime for single molecule junctions from closed-shell DFT within the local density approximation.

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Section: Discussionmentioning

confidence: 99%

Multideterminant assessment of mean-field methods for the description of electron transfer in the weak-coupling regime

2009

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“…Consequently, there is a crossing point at about 7 (for LiF the crossing occurs earlier at ca. 6 [6] ) between the electronically coupled diabatic ionic and covalent potential energy surfaces. Photoexcitation from the ionic ground state of NaI to the first covalent excited state results in bound oscillatory motion in the excited state potential.…”

Section: Introductionmentioning

confidence: 99%

Homolytic versus Heterolytic Dissociation of Alkalimetal Halides: The Effect of Microsolvation

Osuna¹,

Swart²,

Baerends³

et al. 2009

ChemPhysChem

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Herein we report density functional calculations of homolytic and heterolytic dissociation energies of the diatomic alkalimetal halides MX (M=Li, Na, K, Rb, and Cs and X=F, Cl, Br, I, and At) and their corresponding microsolvated structures MX(H(2)O)(n) (n=1 to 4). Our results show that the homolytic dissociation energy of the MX(H(2)O)(n) species increases with the number of water molecules involved in the microsolvated salts. On the other hand, the heterolytic dissociation energy follows exactly the opposite trend. As a result, while for the isolated diatomic alkalimetal halides, homolytic dissociation is always favored over heterolytic dissociation, the latter is preferred for CsF and CsCl already for n=2, and for n=4 it is the preferential mode of dissociation for more than half of the species studied.

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“…The first one is the excessively large number of amplitudes, especially when the full extensivity of the theory is required, and the second, is the difficulty in converging the MRCC equations, resulting from their highly nonlinear structure. The MRexpT method of Hanrath [112,[139][140][141][142] and the C-conditions method of Li and Paldus [92][93][94][95][96][97] seem to offer a promising solution of the first problem. On should also point out that the incomplete model spaces and the C-conditions can also be used in the state-selective framework -in the BW-CC [119] and [60,151], who approximated the core-virtual bi-excited amplitudes by perturbation theory and obtained very good results with a greatly reduced number of variables in the nonlinear CC equations.…”

Section: Discussionmentioning

confidence: 99%

Multireference coupled-cluster Ansatz

Jeziorski

2010

Molecular Physics

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

Cited by 20 publications

References 56 publications

Multideterminant assessment of mean-field methods for the description of electron transfer in the weak-coupling regime

Multideterminant assessment of mean-field methods for the description of electron transfer in the weak-coupling regime

Homolytic versus Heterolytic Dissociation of Alkalimetal Halides: The Effect of Microsolvation

Multireference coupled-cluster Ansatz

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