First experimental photo-detachment spectrum of H2−

Rudnev, V.; Schlösser, M.; Telle, Helmut H.; Ureña, A. González

doi:10.1016/j.cplett.2015.08.066

Cited by 5 publications

(3 citation statements)

References 30 publications

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“…For the atoms and dimers of the groups 1 and 11 the promotion energies are zero and the VS and GS potential energy curves identical; we have χ VS ( at ) = −μ op (at) and the molecular α VP (X 2 , σ ) = −μ op (X 2 ) do not differ either. For the hydrogen dimer, the best experimental results I v (H 2 ) = 16.17 and A v (H 2 ) = – 2.19 give δ α VP (H 2 , σ) = δμ op (H 2 ) = 3% in support of equalization. Adding the zero‐point‐vibration‐energy ZPE = 0.269 eV by clamping the nuclei at R e to obtain I e (H 2 ) = 16.44 further reduces δ α VP (H 2 ) = δμ op (H 2 ) = 0.7% (Table , in parenthesis).…”

Section: The Performance Of Valence‐pair Equilibrationmentioning

confidence: 80%

“…The energy difference between XY and XY + is obtained from (i) theoretical calculations, for example, Refs. [] (ii) molecular photoelectron (PE) spectra, for example, Refs. [] The PE spectra are often assigned to the electron removal from a particular bond, b , for example, Refs.…”

Section: The Performance Of Valence‐pair Equilibrationmentioning

confidence: 99%

“…The updated I and A data are listed in Supporting Information Table S, for their references, see Refs. [].…”

Section: The Performance Of Valence‐pair Equilibrationmentioning

confidence: 99%

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Eliminating symmetry problems in electronegativity equalization and correcting self‐interaction errors in conceptual DFT

Szentpály

2018

J Comput Chem

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The chemical potential is by definition constant in molecules, and electronic charge is in principle equilibrated by bonding. Does electronegativity offer the best scale to unify these principles? According to conceptual density functional theory (c-DFT), the electronegativity equalization (ENE) and chemical potential equalization (CPE) principles seem rigorous and identical. However, the operational formulations of CPE and ENE fail to validate this claim, and frequently dramatic deviations from equalization are reported. We here eliminate the deviations to a very large extent. The problems originate from (i) c-DFT's exclusive reference to ground states and violations of the Wigner-Witmer symmetry constraints for bonding, (ii) electron self-interaction and delocalization errors. The problems are solved, and much more accurate ENE and bond polarities are obtained by replacing the ground-state electronegativity (χ ) by the valence-state electronegativity (χ ) and its generalization, the valence-pair-affinity (VPA, α ). The VPA is a charge dependent pair-sharing potential connected to Ruedenberg's bond theory that emphasizes the role of electron pair-density. The performances of the valence-pair equilibration (VPEq) and c-DFT's operational CPE are compared for 89 molecules with very diverse bond characters, including the "exotic" dimers Be , Mg , B , C , and Mn . The accuracy of VPEq is about 9 times better than that of operational CPE. Without requiring ad hoc calibrations, the VPEq bond polarities agree very well with results of state-of-the-art population analyses, and charges derived from vibrational spectra. A paradigm shift emphasizing valence states seems in order for c-DFT. Electronegativity and the chemical potential should be regarded as separate properties. Copyright © 2018 Wiley Periodicals, Inc.

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Section: The Performance Of Valence‐pair Equilibrationmentioning

confidence: 80%

Section: The Performance Of Valence‐pair Equilibrationmentioning

confidence: 99%

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Eliminating symmetry problems in electronegativity equalization and correcting self‐interaction errors in conceptual DFT

Szentpály

2018

J Comput Chem

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Hardness maximization or equalization? New insights and quantitative relations between hardness increase and bond dissociation energy

Szentpály

2017

J Mol Model

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It has been overlooked that the change of hardness, η, upon bonding is intimately connected to thermochemical cycles, which determine whether hardness is increased according to Pearson's "maximum hardness principle" (MHP) or equalized, as expected by Datta's "hardness equalization principle" (HEP). So far the performances of these likely incompatible "structural principles" have not been compared. Computational validations have been inconclusive because the hardness values and even their qualitative trends change drastically and unsystematically at different levels of theory. Here I elucidate the physical basis of both rules, and shed new light on them from an elementary experimental source. The difference, Δη = η -<η >, of the molecular hardness, η , and the averaged atomic hardness,<η >, is determined by thermochemical cycles involving the bond dissociation energies D of the molecule, D of its cation, and D of its anion. Whether the hardness is increased, equalized or even reduced is strongly influenced by ΔD = 2D - D - D. Quantitative expressions for Δη are obtained, and the principles are tested on 90 molecules and the association reactions forming them. The Wigner-Witmer symmetry constraints on bonding require the valence state (VS) hardness, η , instead of the conventional ground state (GS) hardness, η. Many intriguingly "unpredictable" failures and systematic shortcomings of said "principles" are understood and overcome for the first time, including failures involving exotic and/or challenging molecules, such as Be B, O, and transition metal compounds. New linear relationships are discovered between the MHP hardness increase Δη and the intrinsic bond dissociation energy D . For bond formations, MHP and HEP are not compatible, and HEP does not qualify as an ordering rule.

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Trapping of H2− in aluminum hydride, Al4H14−

Kiran

Bowen

Kandalam

2021

The Journal of Chemical Physics

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Ever since our first experimental and computational identification of Al4H6 as a boron analog [X. Li et al., Science 315, 356 (2007)], studies on aluminum hydrides unveiled a richer pattern of structural motifs. These include aluminum-rich hydrides, which follow shell closing electron counting models; stoichiometric clusters (called baby crystals), which structurally correspond to the bulk alane; and more. In this regard, a mass spectral identification of unusually high intense peak of Al4H14−, which has two hydrogen atoms beyond stoichiometry, has remained mostly unresolved [X. Li et al., J. Chem. Phys. 132, 241103 (2010)]. In this Communication, with the help of global minima methods and density functional theory-based calculations, we identify the lowest energy bound structure with a unique Al–H–H–Al bonding. Our electronic structural analysis reveals that two Al2H6 units trap a transient, metastable H2−. In other words, three stable molecules, two Al2H6 and an H2, are held together by a single electron. Our studies provide a pathway to stabilize transient species by making them part of a more extensive system.

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First experimental photo-detachment spectrum of H2−

Cited by 5 publications

References 30 publications

Eliminating symmetry problems in electronegativity equalization and correcting self‐interaction errors in conceptual DFT

Eliminating symmetry problems in electronegativity equalization and correcting self‐interaction errors in conceptual DFT

Hardness maximization or equalization? New insights and quantitative relations between hardness increase and bond dissociation energy

Trapping of H2− in aluminum hydride, Al4H14−

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