Chemistry with semi-classical electrons: reaction trajectories auto-generated by sub-atomistic force fields

Bai, Chen; Kale, Seyit; Herzfeld, Judith

doi:10.1039/c7sc01181d

Cited by 13 publications

(24 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Inasmuch as it is difficult to detect concentration the SL ions in water directly, we rely on studies based on the terahertz absorption measurements 21 , as well as on molecular dynamics simulations that take into account the auto-dissociation events in the frame of the semi-classical approach 26 . Both studies conclude that the approximate concentration of the SL ions is about 1 M (or about 2%).…”

Section: Results and Analysismentioning

confidence: 99%

“…The formation-recombination pathway of SL ions is intermolecular and loop-shaped 19 , and it yields “instantaneous” SL concentrations much higher than LL’s ones 20 – 22 , but random thermal disturbances allow transfer of SL ions to the LL pH-active and ion populations 23 , 24 . Importantly, because of their short lifetime ( ps) SL ions contribute only little to dc conductivity 25 , 26 , yet their concentration can be sufficiently large ( M) to drive the Debye relaxation of water 22 , 25 .…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Revealing excess protons in the infrared spectrum of liquid water

Артемов

Uykur

Roh

et al. 2020

Sci Rep

View full text Add to dashboard Cite

The most common species in liquid water, next to neutral molecules, are the and ions. In a dynamic picture, their exact concentrations depend on the time scale at which these are probed. Here, using a spectral-weight analysis, we experimentally resolve the fingerprints of the elusive fluctuations-born short-living , , , and ions in the IR spectra of light ( ), heavy ( ), and semi-heavy (HDO) water. We find that short-living ions, with concentrations reaching of the content of water molecules, coexist with long-living pH-active ions on the picosecond timescale, thus making liquid water an effective ionic liquid in femtochemistry.

show abstract

Section: Results and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Revealing excess protons in the infrared spectrum of liquid water

Артемов

Uykur

Roh

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…Inasmuch as it is difficult to detect concentration the SL ions in water directly, we rely on studies based on the terahertz absorption measurements [18], as well as on molecular dynamics simulations that take into account the auto-dissociation events in the frame of the semiclassical approach [21]. Both studies conclude that the approximate concentration of the SL ions is about 1 M (or about 2%).…”

Section: Resultsmentioning

confidence: 99%

“…However, the "instantaneous" concentration of the SL ions is much higher than the LL's ones [17][18][19]. The SL ionic concentration of about 1 M was suggested to be responsible for the Debye relaxation of water (a strong absorption band in the gigahertz range) [19,20], but, because of the short lifetime (3 ps) of these ions, their contribution to the dc conductivity is small [20,21].…”

Section: Introductionmentioning

confidence: 99%

Revealing excess protons in the infrared spectrum of liquid water

Artemov,

Uykur,

Roh

et al. 2019

Preprint

View full text Add to dashboard Cite

The most common species in liquid water, next to neutral H2O molecules, are the H3O + and OH − ions. Though they contribute to the infrared (IR) spectrum, they remain hidden within the broad absoption lines of neutral molecules. This severely hinders the interpretation of the spectroscopic data. Using a spectral-weight analysis, here we experimentally resolve the fingerprints of H3O * , DH2O * , HD2O * , and D3O * ions in the IR spectra of light (H2O), heavy (D2O), and semi-heavy (HDO) water. We calculate the normal vibration modes of these ions, assign them to certain spectral features, and determine the ion concentrations. We find that the fluctuations-born short-living ions with a concentration of about two percent of the content of water molecules, coexist with long-living pH-active ions. We conclude that water is a "two-percent ionic liquid" at least on timescale shorter than picoseconds.

show abstract

“…Sub‐atomistic force fields seek to devise potentials for the interactions of semi‐classical electrons. [11] The approach is similar to classical molecular mechanics except that electrons are made explicit and independently mobile, with the advantage that polarizability and bond making/breaking are described in a natural, self‐consistent and orbital‐free manner, without assignment of atom types. In earlier work, we focused on the importance of exchange for stabilizing high spin states, such as the triplet ground states of the oxygen atom and dioxygen.…”

Section: Discussionmentioning

confidence: 99%

Bending the Curve: Molecular Manifestations of Electron Antisymmetry

Herzfeld

Song

et al. 2021

ChemistryOpen

Self Cite

View full text Add to dashboard Cite

As very light fermions, electrons are governed by antisymmetric wave functions that lead to exchange integrals in the evaluation of the energy. Here we use the localized representation of orbitals to decompose the electronic energy in a fashion that isolates the enigmatic exchange contributions and characterizes their distinctive control over electron distributions. The key to this completely general analysis is considering the electrons in groups of three, drawing attention to the curvatures of pair potentials, rather than just their amplitudes and slopes. We show that a positive curvature at short distances is essential for the mutual distancing of electrons and a negative curvature at longer distances is essential to account for the influence of lone pairs on bond torsion. Neither curvature is available in the absence of the exchange contributions. Thus, although exchange energies are much shorter range than Coulomb energies, their influence on molecular geometry is profound and readily understood.

show abstract

Chemistry with semi-classical electrons: reaction trajectories auto-generated by sub-atomistic force fields

Abstract: Suitable force fields animate “Lewis-dots” with sufficient accuracy to efficiently predict reaction pathways without prior knowledge of products.

Cited by 13 publications

References 38 publications

Revealing excess protons in the infrared spectrum of liquid water

Revealing excess protons in the infrared spectrum of liquid water

Revealing excess protons in the infrared spectrum of liquid water

Bending the Curve: Molecular Manifestations of Electron Antisymmetry

Contact Info

Product

Resources

About