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Browsing Chemistry & Biochemistry by Issue Date

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Two-photon imaging of Zn2+ dynamics in mossy fiber boutons of adult hippocampal slices 

Khan, Mustafa; Goldsmith, Christian R.; Huang, Zhen; Georgiou, John; Luyben, Thomas T.; Roder, John C.; Lippard, Stephen J.; Okamoto, Kenichi (2020-01-16)
Mossy fiber termini in the hippocampus accumulate Zn2+, which is released with glutamate from synaptic vesicles upon neural excitation. Understanding the spatiotemporal regulation of mobile Zn2+ at the synaptic level is ...

Excitation energies, photoionization cross sections, and asymmetry parameters of the methyl and silyl radicals 

Velasco, A. M.; Lavin, C.; Dolgounitcheva, O.; Ortiz, J. V. (2020-01-16)
Vertical excitation energies of the methyl and silyl radicals were inferred from ab initio electron propagator calculations on the electron affinities of CH3 + and SiH3 +. Photoionization cross sections and angular ...

Double Rydberg anions with solvated ammonium kernels: Electron binding energies and Dyson orbitals 

Diaz-Tinoco, Manuel; Ortiz, J.V. (2020-03-10)
Ab initio electron-propagator calculations on the electron detachment energies and associated Dyson orbitals of NnH3n+1- for n = 1-5 confirm the assignment of low-energy peaks in anion photoelectron spectra to double Rydberg ...

Dependence of the multipole moments, static polarizabilities, and static hyperpolarizabilities of the hydrogen molecule on the H-H separation in the ground singlet state 

Miliordos, Evangelos; Hunt, Katharine L. C.; https://orcid.org/0000-0003-3471-7133 (2020-06-25)
In this work, we provide values for the quadrupole moment Theta, the hexadecapole moment Phi, the dipole polarizability alpha, the quadrupole polarizability C, the dipole-octopole polarizability E, the second dipole ...

First-order symmetry-adapted perturbation theory for multiplet splittings 

Patkowski, Konrad; Zuchowski, Piotr S.; Smith, Daniel G. A.; https://orcid.org/0000-0002-4468-207X (2020-06-25)
We present a symmetry-adapted perturbation theory (SAPT) for the interaction of two high-spin open-shell molecules (described by their restricted open-shell Hartree-Fock determinants) resulting in low-spin states of the ...

Communication: Water activation and splitting by single metal-atom anions 

Liu, Gaoxiang; Miliordos, Evangelos; Ciborowski, Sandra M.; Tschurl, Martin; Boesl, Ulrich; Heiz, Ulrich; Zhang, Xinxing; Xantheas, Sotiris S.; Bowen, Kit; https://orcid.org/0000-0003-3471-7133 (2020-06-25)
We report experimental and computational results pertaining to the activation and splitting of single water molecules by single atomic platinum anions. The anion photoelectron spectra of [Pt(H2O)](-), formed under different ...

On the accuracy of explicitly correlated coupled-cluster interaction energies - have orbital results been beaten yet? 

Patkowski, Konrad (2020-08-20)
The basis set convergence of weak interaction energies for dimers of noble gases helium through krypton is studied for six variants of the explicitly correlated, frozen geminal coupled-cluster singles, doubles, and ...

Interpretation of the photoelectron spectra of superalkali species: Na3O and Na3O- 

Zein, S; Ortiz, J. V.; Ortiz, Joseph Vincent (2020-08-20)
Recently measured photoelectron spectra of the Na3O- anion have been interpreted with the aid of ab initio electron propagator calculations. As in the case of the Li3O-, we propose that the photoionization of ground and ...

Valence and diffuse-bound anions of noble-gas complexes with uracil 

Streit, Livia; Dolgounitcheva, O.; Zakrzewski, V. G.; Ortiz, J. V.; Ortiz, Joseph Vincent (2020-08-20)
Valence-bound (VB) and diffuse-bound (DB) anions of noble-gas (Ar, Kr, and Xe) complexes with uracil have been studied with ab initio methods. MP2 optimizations revealed minima corresponding to anions of both kinds in ...

OH3- and O2H5- double Rydberg anions: Predictions and comparisons with NH4- and N2H7- 

Melin, Junia; Ortiz, J.V. (2021-01-26)
A low barrier in the reaction pathway between the double Rydberg isomer of OH3 − and a hydride-water complex indicates that the former species is more difficult to isolate and characterize through anion photoelectron ...

Surface Green’s function calculations: A nonrecursive scheme with an infinite number of principal layers 

Kletsov, Aleksey; Dahnovsky, Yuri; Ortiz, J.V. (2021-01-26)
A novel computational method for a surface Green’s function matrix is introduced for the calculation of electrical current in molecular wires. The proposed nonrecursive approach includes an infinite number of principal ...

Partial photoionization cross sections of and Rydberg radicals 

Velasco, A.M.; Lavin, C.; Martin, I.; Melin, J.; Ortiz, J.V. (2021-01-26)
ammonium and oxonium Rydberg radicals from the outermost, occupied orbitals of their respective ground states are reported. These properties are known to be relevant in photoelectron dynamics studies. For the present ...

Assessment of transition operator reference states in electron propagator calculations 

Flores-Moreno, Roberto; Zakrzewski, V. G.; Ortiz, J.V. (2021-01-26)
The transition operator method combined with second-order, self-energy corrections to the electron propagator TOEP2 may be used to calculate valence and core-electron binding energies. This method is tested on a set of ...

Integral approximations in ab initio, electron propagator calculations 

Flores-Moreno, Roberto; Ortiz, J.V. (2021-01-26)
Treatments of interelectronic repulsion that avoid four-center integrals have been incorporated in ab initio, electron-propagator calculations with diagonal self-energy matrices. Whereas the formal scaling of arithmetic ...

Sequential addition of H2O, CH3OH, and NH3 to Al3O3-: A theoretical study 

Guevara-Garcia, Alfredo; Martinez, Ana; Ortiz, J.V. (2021-01-26)
Photoelectron spectra of two species, Al3O3(H2O)(2)(-) and Al3O3(CH3OH)(2)(-), that are produced by the addition of two water or methanol molecules to Al3O3- are interpreted with density-functional geometry optimizations ...

Electron binding energies and Dyson orbitals of Al(5)O(m)(-) (m=3,4,5) and Al(5)O(5)H(2)(-) 

Guevara-Garcia, Alfredo; Martinez, Ana; Ortiz, J.V. (2021-01-26)
Photoelectron spectra of Al5Om − m=3–5 and of the anion produced by the dissociative adsorption of a water molecule by Al5O4 − are interpreted with density-functional geometry optimizations and electron-propagator ...

Direct ΔMBPT(2) method for ionization potentials, electron affinities, and excitation energies using fractional occupation numbers 

Beste, Ariana; Vazquez-Mayagoitia, Alvaro; Ortiz, J. V.; Ortiz, Joseph V. (2020-01-16)
A direct method (D-ΔMBPT(2)) to calculate second-order ionization potentials (IPs), electron affinities (EAs), and excitation energies is developed. The ΔMBPT(2) method is defined as the correlated extension of the ΔHF ...

A generalized any-particle propagator theory: Prediction of proton affinities and acidity properties with the proton propagator 

Diaz-Tinoco, Manuel; Romero, Jonathan; Ortiz, J. V.; Reyes, Andres; Flores-Moreno, Roberto; Ortiz, Joseph V. (2020-01-16)
We have recently extended the electron propagator theory to the treatment of any type of particle using an Any-Particle Molecular Orbital (APMO) wavefunction as reference state. This approach, called APMO/PT, has been ...

Highly accurate potential energy surface for the He-H-2 dimer 

Bakr, Brandon W.; Smith, Daniel G. A.; Patkowski, Konrad; Brandon W. Bakr, Daniel G. A. Smith, and Konrad Patkowski (2020-01-16)
A new highly accurate interaction potential is constructed for the He–H2 van der Waals complex. This potential is fitted to 1900 ab initio energies computed at the very large-basis coupled-cluster level and augmented by ...

Basis set converged weak interaction energies from conventional and explicitly correlated coupled-cluster approach 

Patkowski, Konrad (2020-01-16)
Interaction energies for seven weakly bound dimers involving helium, argon, water, and methane are computed using large correlation-consistent basis sets augmented with bond functions. The estimates of the coupled-cluster ...