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J. V. Ortiz - One of the best experts on this subject based on the ideXlab platform.

  • Tautomeric forms of azolide anions: vertical Electron Detachment energies and Dyson orbitals.
    The journal of physical chemistry. A, 2007
    Co-Authors: Junia Melin, Raman K. Singh, Manoj Mishra, J. V. Ortiz
    Abstract:

    Several decouplings of the Electron propagator, including the relatively new P3+ approximation for the selfenergy, have been used to calculate vertical Electron Detachment energies of tautomeric forms of closedshell, pentagonal, aromatic anions in which ring carbons without bonds to hydrogens appear. This study extends previous work in which the most stable forms of anionic, five-member rings with one to five nitrogens were considered. Whereas the lowest Electron Detachment energies sometimes are assigned by Koopmans’s theorem results to ﷿ orbital vacancies, Electron propagator calculations always obtain U orbital vacancies for the ground states of the doublet radicals. Higher Electron Detachment energies that correspond to excited doublets with ﷿ vacancies also are presented. The predicted transition energies are in good agreement with low-intensity peaks in recent anion photoElectron spectra that have been assigned to less stable, tautomeric forms of these anions.

  • Electron propagator studies of vertical Electron Detachment energies and isomerism in purinic deoxyribonucleotides
    International Journal of Quantum Chemistry, 2007
    Co-Authors: V. V. Zakjevskii, Olga Dolgounitcheva, V. G. Zakrzewski, J. V. Ortiz
    Abstract:

    Electron propagator calculations in the Partial Third Order Approximation were performed on major and minor conformational isomers of 2′-deoxyriboadenosine 5′-monophosphate (dAMP−) and 2′-deoxyriboguanosine 5′-monophosphate (dGMP−). Resulting vertical Electron Detachment energies (VEDEs) correspond extremely well with the experimental values available from the literature. The first VEDE in dGMP− is caused by Electron Detachment from the guanine moiety and is well separated from the rest of the spectrum. The offset of the ionization band in the case of dAMP− is caused by two, almost degenerate Detachments, one from the phosphate group and another from the adenine π1 molecular orbital. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007

  • Base and Phosphate Electron Detachment Energies of Deoxyribonucleotide Anions
    Journal of the American Chemical Society, 2006
    Co-Authors: Viatcheslav V. Zakjevskii, V. G. Zakrzewski, Olga Dolgounitcheva, Samuel J. King, J. V. Ortiz
    Abstract:

    PhotoElectron spectra of deoxyribonucleotide anions are interpreted with ab initio, Electron propagator calculations. Ground-state structures display hydrogen bonds which are not present in less stable minima that resemble Watson-Crick fragment geometries. For the adenosine and thymidine anions, there are two vertical Electron Detachment energies (VEDEs) within 0.1 eV of each other that correspond to phosphate- and base-centered Dyson orbitals (DOs). The first VEDE of the cytidine anion belongs to a phosphate-centered DO. The anomalously low VEDE of the guanosine anion is assigned to a base-centered, pi DO. Higher VEDEs of all four anions also are assigned.

  • Structures and Electron Detachment energies of uracil anions
    Chemical Physics Letters, 1999
    Co-Authors: O. Dolgounitcheva, V. G. Zakrzewski, J. V. Ortiz
    Abstract:

    Abstract Uracil and its radical anions were studied with second-order, many-body perturbation theory, coupled-cluster theory and Electron propagator methods with large, diffuse, atom-centered basis sets. All structures were optimized and two minima were found for anionic forms: one corresponding to a 2 A′, diffuse-bound state and another corresponding to a 2 A, non-planar, covalent-bound state. The optimized 2 A′ anionic structure is lower in energy than the neutral form. The vertical Electron Detachment energy (VEDE) of this structure is very close to the experimentally observed value. A large, positive VEDE was found for the 2 A, covalent-bound anion.

  • Electron Detachment energies of closed-shell anions calculated with a renormalized Electron propagator
    Chemical Physics Letters, 1998
    Co-Authors: J. V. Ortiz
    Abstract:

    Abstract Vertical Electron Detachment energies of 10 closed-shell anions (F − , OH − , NH 2 − , Cl − , SH − , PH 2 − , CN − , BO − , AlO − , AlS − ) are calculated with an ab initio implementation of a new Electron propagator approximation. In this method, the reference state is defined in terms of the Brueckner-doubles coupled-cluster wavefunction. The operator manifold consists of hole (h), particle (p), shakeup (2hp) and shakeon (2ph) operators. Couplings between 2hp and 2ph operators are neglected. Augmented correlation-consistent triple- ζ basis sets are used. Estimates of the corresponding adiabatic Electron Detachment energies (Electron affinities of the neutrals) are compared with photoElectron experiments. The maximum error is 0.14 eV; the average absolute error is 0.05 eV.

Nick L Aleksandrov - One of the best experts on this subject based on the ideXlab platform.

  • Monte Carlo simulation of Electron Detachment properties for {{\text{O}_{2}^{{}}}^{-}} ions in oxygen and oxygen:nitrogen mixtures
    Plasma Sources Science and Technology, 2015
    Co-Authors: Alexander Ponomarev, Nick L Aleksandrov
    Abstract:

    Electron Detachment properties of ions in pure oxygen and oxygen:nitrogen mixtures have been studied by a Monte Carlo technique for the reduced electric fields up to 350 Td (1 Td = 10−17 Vcm2). Swarm parameters were calculated for unexcited and vibrationally excited ions taking into account vibrational transfer and relaxation, charge transfer and Electron Detachment. The cross sections for vibrational transfer and relaxation in collisions between ions and O2 molecules were calculated on the basis of the statistical approach that had been successfully used in our previous work to simulate the effect of vibrational excitation and the effect of electric field on Electron Detachment. Good agreement between the calculated Detachment rate and available measurements in oxygen were obtained over a wide range of reduced electric fields without using adjusted parameters. The method was used to calculate Detachment rates in air and in some other oxygen:nitrogen mixtures and to study the effect of gas temperature on Electron Detachment.

  • monte carlo simulation of Electron Detachment properties for text o _ 2 ions in oxygen and oxygen nitrogen mixtures
    Plasma Sources Science and Technology, 2015
    Co-Authors: Alexander Ponomarev, Nick L Aleksandrov
    Abstract:

    Electron Detachment properties of ions in pure oxygen and oxygen:nitrogen mixtures have been studied by a Monte Carlo technique for the reduced electric fields up to 350 Td (1 Td = 10−17 Vcm2). Swarm parameters were calculated for unexcited and vibrationally excited ions taking into account vibrational transfer and relaxation, charge transfer and Electron Detachment. The cross sections for vibrational transfer and relaxation in collisions between ions and O2 molecules were calculated on the basis of the statistical approach that had been successfully used in our previous work to simulate the effect of vibrational excitation and the effect of electric field on Electron Detachment. Good agreement between the calculated Detachment rate and available measurements in oxygen were obtained over a wide range of reduced electric fields without using adjusted parameters. The method was used to calculate Detachment rates in air and in some other oxygen:nitrogen mixtures and to study the effect of gas temperature on Electron Detachment.

Frank Kjeldsen - One of the best experts on this subject based on the ideXlab platform.

Roman A. Zubarev - One of the best experts on this subject based on the ideXlab platform.

Alexander Ponomarev - One of the best experts on this subject based on the ideXlab platform.

  • Monte Carlo simulation of Electron Detachment properties for {{\text{O}_{2}^{{}}}^{-}} ions in oxygen and oxygen:nitrogen mixtures
    Plasma Sources Science and Technology, 2015
    Co-Authors: Alexander Ponomarev, Nick L Aleksandrov
    Abstract:

    Electron Detachment properties of ions in pure oxygen and oxygen:nitrogen mixtures have been studied by a Monte Carlo technique for the reduced electric fields up to 350 Td (1 Td = 10−17 Vcm2). Swarm parameters were calculated for unexcited and vibrationally excited ions taking into account vibrational transfer and relaxation, charge transfer and Electron Detachment. The cross sections for vibrational transfer and relaxation in collisions between ions and O2 molecules were calculated on the basis of the statistical approach that had been successfully used in our previous work to simulate the effect of vibrational excitation and the effect of electric field on Electron Detachment. Good agreement between the calculated Detachment rate and available measurements in oxygen were obtained over a wide range of reduced electric fields without using adjusted parameters. The method was used to calculate Detachment rates in air and in some other oxygen:nitrogen mixtures and to study the effect of gas temperature on Electron Detachment.

  • monte carlo simulation of Electron Detachment properties for text o _ 2 ions in oxygen and oxygen nitrogen mixtures
    Plasma Sources Science and Technology, 2015
    Co-Authors: Alexander Ponomarev, Nick L Aleksandrov
    Abstract:

    Electron Detachment properties of ions in pure oxygen and oxygen:nitrogen mixtures have been studied by a Monte Carlo technique for the reduced electric fields up to 350 Td (1 Td = 10−17 Vcm2). Swarm parameters were calculated for unexcited and vibrationally excited ions taking into account vibrational transfer and relaxation, charge transfer and Electron Detachment. The cross sections for vibrational transfer and relaxation in collisions between ions and O2 molecules were calculated on the basis of the statistical approach that had been successfully used in our previous work to simulate the effect of vibrational excitation and the effect of electric field on Electron Detachment. Good agreement between the calculated Detachment rate and available measurements in oxygen were obtained over a wide range of reduced electric fields without using adjusted parameters. The method was used to calculate Detachment rates in air and in some other oxygen:nitrogen mixtures and to study the effect of gas temperature on Electron Detachment.