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Joachim Maier - One of the best experts on this subject based on the ideXlab platform.
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proton hydroxide ion and oxide ion affinities of Closed Shell oxides importance for the hydration reaction and correlation to electronic structure
Journal of Physical Chemistry C, 2020Co-Authors: Tor S. Bjørheim, Maximilian F Hoedl, Rotraut Merkle, Eugene A. Kotomin, Joachim MaierAbstract:Phenomenologically, the enthalpy of the dissociative water incorporation (hydration) of oxides is often found to be more favorable for more basic oxides. In the present work, we investigate proton, hydroxide ion, and oxide ion affinities (PA, HA, and OA) for 19 Closed-Shell oxides ranging from Li2O and Cs2O to TiO2, SnO2, and SiO2, including also perovskites such as SrTiO3 and BaZrO3 using first-principles defect calculations and thermochemical cycles. The proton affinity is found to play a predominant role in the hydration thermodynamics. The ion affinities are strongly correlated with the oxides’ electronic structure (specifically, the ionization potential (IP)). This intriguing correlation between PA and IP holds also for gaseous O species, suggesting a very general origin. Understanding the major factors controlling a metal oxide’s susceptibility for dissociative hydration of oxygen vacancies is not only of fundamental interest but also key to the successful development of novel mixed proton–electron ...
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proton hydroxide ion and oxide ion affinities of Closed Shell oxides importance for the hydration reaction and correlation to electronic structure
The Journal of Physical Chemistry, 2019Co-Authors: Tor S. Bjørheim, Maximilian F Hoedl, Rotraut Merkle, Eugene A. Kotomin, Joachim MaierAbstract:Phenomenologically, the enthalpy of the dissociative water incorporation (hydration) of oxides is often found to be more favorable for more basic oxides. In the present work, we investigate proton, hydroxide ion, and oxide ion affinities (PA, HA, and OA) for 19 Closed-Shell oxides ranging from Li₂O and Cs₂O to TiO₂, SnO₂, and SiO₂, including also perovskites such as SrTiO₃ and BaZrO₃ using first-principles defect calculations and thermochemical cycles. The proton affinity is found to play a predominant role in the hydration thermodynamics. The ion affinities are strongly correlated with the oxides’ electronic structure (specifically, the ionization potential (IP)). This intriguing correlation between PA and IP holds also for gaseous O species, suggesting a very general origin. Understanding the major factors controlling a metal oxide’s susceptibility for dissociative hydration of oxygen vacancies is not only of fundamental interest but also key to the successful development of novel mixed proton–electron conducting oxides for protonic ceramic fuel and electrolyzer cells. In addition to elucidating the hydration reaction, these ion affinities also serve a more general purpose, as they can be used to predict the oxides’ tendency to in-/excorporate a specific ion.
Eugene A. Kotomin - One of the best experts on this subject based on the ideXlab platform.
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proton hydroxide ion and oxide ion affinities of Closed Shell oxides importance for the hydration reaction and correlation to electronic structure
Journal of Physical Chemistry C, 2020Co-Authors: Tor S. Bjørheim, Maximilian F Hoedl, Rotraut Merkle, Eugene A. Kotomin, Joachim MaierAbstract:Phenomenologically, the enthalpy of the dissociative water incorporation (hydration) of oxides is often found to be more favorable for more basic oxides. In the present work, we investigate proton, hydroxide ion, and oxide ion affinities (PA, HA, and OA) for 19 Closed-Shell oxides ranging from Li2O and Cs2O to TiO2, SnO2, and SiO2, including also perovskites such as SrTiO3 and BaZrO3 using first-principles defect calculations and thermochemical cycles. The proton affinity is found to play a predominant role in the hydration thermodynamics. The ion affinities are strongly correlated with the oxides’ electronic structure (specifically, the ionization potential (IP)). This intriguing correlation between PA and IP holds also for gaseous O species, suggesting a very general origin. Understanding the major factors controlling a metal oxide’s susceptibility for dissociative hydration of oxygen vacancies is not only of fundamental interest but also key to the successful development of novel mixed proton–electron ...
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proton hydroxide ion and oxide ion affinities of Closed Shell oxides importance for the hydration reaction and correlation to electronic structure
The Journal of Physical Chemistry, 2019Co-Authors: Tor S. Bjørheim, Maximilian F Hoedl, Rotraut Merkle, Eugene A. Kotomin, Joachim MaierAbstract:Phenomenologically, the enthalpy of the dissociative water incorporation (hydration) of oxides is often found to be more favorable for more basic oxides. In the present work, we investigate proton, hydroxide ion, and oxide ion affinities (PA, HA, and OA) for 19 Closed-Shell oxides ranging from Li₂O and Cs₂O to TiO₂, SnO₂, and SiO₂, including also perovskites such as SrTiO₃ and BaZrO₃ using first-principles defect calculations and thermochemical cycles. The proton affinity is found to play a predominant role in the hydration thermodynamics. The ion affinities are strongly correlated with the oxides’ electronic structure (specifically, the ionization potential (IP)). This intriguing correlation between PA and IP holds also for gaseous O species, suggesting a very general origin. Understanding the major factors controlling a metal oxide’s susceptibility for dissociative hydration of oxygen vacancies is not only of fundamental interest but also key to the successful development of novel mixed proton–electron conducting oxides for protonic ceramic fuel and electrolyzer cells. In addition to elucidating the hydration reaction, these ion affinities also serve a more general purpose, as they can be used to predict the oxides’ tendency to in-/excorporate a specific ion.
Donald G Truhlar - One of the best experts on this subject based on the ideXlab platform.
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Is the Inversion of Phosphorus Trihalides (PF3, PCl3, PBr3, and PI3) a Diradical Process?
2018Co-Authors: Zoltan Varga, Pragya Verma, Donald G TruhlarAbstract:This work explores possible reaction paths for the inversion of a series of trigonal pyramidal phosphorus trihalides, PF3, PCl3, PBr3, and PI3, and it especially addresses the question of whether and when the bonding of the lowest-energy species along the inversion paths should be described as a hyper-open-Shell diradical. The various paths for inversion are calculated using a single-reference method within the framework of Kohn–Sham density functional theory and also with multireference wave function methods. Our calculated results using both kinds of methods show that, for all the halogens studied (F, Cl, Br, and I), the lowest-energy singlet path for the inversion occurs by the formation of a C2v transition structure rather than a D3h transition structure. This geometrical preference agrees with what has been inferred previously based on Closed-Shell singlet calculations. But in the present study, we examined not only Closed-Shell singlet transition states but also open-Shell singlet states and triplet states for calculating stationary points and inversion paths, and for some of the phosphorus trihalides, we found that paths involving open-Shell configurations are lower in energy than those restricted to Closed-Shell configurations. We analyzed the changes along the paths in terms of hybridization and orientation of the frontier orbitals and in terms of locally avoided crossings, and the extent of the diradical character was quantified by calculating the effective number of unpaired electrons. Even for the singlet inversion path that goes via a D3h structure, the barrier for PF3, PCl3, and PBr3 is higher for a Closed-Shell singlet spin state than for the open-Shell singlet configuration. Furthermore, the energy of the triplet D3h structure is below even that of the open-Shell D3h singlet for PCl3, PBr3, and PI3. This necessitates rethinking the role of open-Shell states in nominally Closed-Shell processes
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components of the bond energy in polar diatomic molecules radicals and ions formed by group 1 and group 2 metal atoms
Journal of Chemical Theory and Computation, 2015Co-Authors: Haoyu S Yu, Donald G TruhlarAbstract:Although many transition metal complexes are known to have high multireference character, the multireference character of main-group Closed-Shell singlet diatomic molecules like BeF, CaO, and MgO has been less studied. However, many group-1 and group-2 diatomic molecules do have multireference character, and they provide informative systems for studying multireference character because they are simpler than transition metal compounds. The goal of the present work is to understand these multireference systems better so that, ultimately, we can apply what we learn to more complicated multireference systems and to the design of new exchange-correlation functionals for treating multireference systems more adequately. Fourteen main-group diatomic molecules and one triatomic molecule (including radicals, cations, and anions, as well as neutral Closed-Shell species) have been studied for this article. Eight of these molecules contain a group-1 element, and six contain a group-2 element. Seven of these molecules ...
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testing noncollinear spin flip collinear spin flip and conventional time dependent density functional theory for predicting electronic excitation energies of Closed Shell atoms
Journal of Chemical Theory and Computation, 2014Co-Authors: Ke R Yang, Donald G TruhlarAbstract:Conventional time-dependent density functional theory (TDDFT) is based on a Closed-Shell Kohn-Sham (KS) singlet ground state with the adiabatic approximation, using either linear response (KS-LR) or the Tamm-Dancoff approximation (KS-TDA); these methods can only directly predict singly excited states. This deficiency can be overcome by using a triplet state as the reference in the KS-TDA approximation and "exciting" the singlet by a spin flip (SF) from the triplet; this is the method suggested by Krylov and co-workers, and we abbreviate this procedure as SF-KS-TDA. SF-KS-TDA can be applied either with the original collinear kernel of Krylov and co-workers or with a noncollinear kernel, as suggested by Wang and Ziegler. The SF-KS-TDA method does bring some new practical difficulties into play, but it can at least formally model doubly excited states and states with double-excitation character, so it might be more useful than conventional TDDFT (both KS-LR and KS-TDA) for photochemistry if these additional difficulties can be surmounted and if it is accurate with existing approximate exchange-correlation functionals. In the present work, we carried out calculations specifically designed to understand better the accuracy and limitations of the conventional TDDFT and SF-KS-TDA methods; we did this by studying Closed-Shell atoms and Closed-Shell monatomic cations because they provide a simple but challenging testing ground for what we might expect in studying the photochemistry of molecules with Closed-Shell ground states. To test their accuracy, we applied conventional KS-LR and KS-TDA and 18 versions of SF-KS-TDA (nine collinear and nine noncollinear) to the same set of vertical excitation energies (including both Rydberg and valence excitations) of Be, B(+), Ne, Na(+), Mg, and Al(+). We did this for 10 exchange-correlation functionals of various types, both local and nonlocal. We found that the GVWN5 and M06 functionals with nonlocal kernels in spin-flip calculations can both have accuracy competitive to CASPT2 calculations. When the results were averaged over all 36 test energy differences, seven (GVWN5, M06, B3PW91, LRC-ωPBE, LRC-ωPBEh, PBE, and M06-2X) of the 10 studied density functionals had smaller mean unsigned errors for noncollinear calculations than the mean unsigned error of the best functional (M06-2X) for either conventional KS-TDA or KS-LR.
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testing noncollinear spin flip collinear spin flip and conventional time dependent density functional theory for predicting electronic excitation energies of Closed Shell atoms
Journal of Chemical Theory and Computation, 2014Co-Authors: Xuefei Xu, Ke R Yang, Donald G TruhlarAbstract:Conventional time-dependent density functional theory (TDDFT) is based on a Closed-Shell Kohn–Sham (KS) singlet ground state with the adiabatic approximation, using either linear response (KS-LR) or the Tamm–Dancoff approximation (KS-TDA); these methods can only directly predict singly excited states. This deficiency can be overcome by using a triplet state as the reference in the KS-TDA approximation and “exciting” the singlet by a spin flip (SF) from the triplet; this is the method suggested by Krylov and co-workers, and we abbreviate this procedure as SF-KS-TDA. SF-KS-TDA can be applied either with the original collinear kernel of Krylov and co-workers or with a noncollinear kernel, as suggested by Wang and Ziegler. The SF-KS-TDA method does bring some new practical difficulties into play, but it can at least formally model doubly excited states and states with double-excitation character, so it might be more useful than conventional TDDFT (both KS-LR and KS-TDA) for photochemistry if these additional ...
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Testing Noncollinear Spin-Flip, Collinear Spin-Flip, and Conventional Time-Dependent Density Functional Theory for Predicting Electronic Excitation Energies of Closed-Shell Atoms
2014Co-Authors: Ke R Yang, Donald G TruhlarAbstract:Conventional time-dependent density functional theory (TDDFT) is based on a Closed-Shell Kohn–Sham (KS) singlet ground state with the adiabatic approximation, using either linear response (KS-LR) or the Tamm–Dancoff approximation (KS-TDA); these methods can only directly predict singly excited states. This deficiency can be overcome by using a triplet state as the reference in the KS-TDA approximation and “exciting” the singlet by a spin flip (SF) from the triplet; this is the method suggested by Krylov and co-workers, and we abbreviate this procedure as SF-KS-TDA. SF-KS-TDA can be applied either with the original collinear kernel of Krylov and co-workers or with a noncollinear kernel, as suggested by Wang and Ziegler. The SF-KS-TDA method does bring some new practical difficulties into play, but it can at least formally model doubly excited states and states with double-excitation character, so it might be more useful than conventional TDDFT (both KS-LR and KS-TDA) for photochemistry if these additional difficulties can be surmounted and if it is accurate with existing approximate exchange–correlation functionals. In the present work, we carried out calculations specifically designed to understand better the accuracy and limitations of the conventional TDDFT and SF-KS-TDA methods; we did this by studying Closed-Shell atoms and Closed-Shell monatomic cations because they provide a simple but challenging testing ground for what we might expect in studying the photochemistry of molecules with Closed-Shell ground states. To test their accuracy, we applied conventional KS-LR and KS-TDA and 18 versions of SF-KS-TDA (nine collinear and nine noncollinear) to the same set of vertical excitation energies (including both Rydberg and valence excitations) of Be, B+, Ne, Na+, Mg, and Al+. We did this for 10 exchange–correlation functionals of various types, both local and nonlocal. We found that the GVWN5 and M06 functionals with nonlocal kernels in spin-flip calculations can both have accuracy competitive to CASPT2 calculations. When the results were averaged over all 36 test energy differences, seven (GVWN5, M06, B3PW91, LRC-ωPBE, LRC-ωPBEh, PBE, and M06-2X) of the 10 studied density functionals had smaller mean unsigned errors for noncollinear calculations than the mean unsigned error of the best functional (M06-2X) for either conventional KS-TDA or KS-LR
J V Ortiz - One of the best experts on this subject based on the ideXlab platform.
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nr2 and p3 accurate efficient electron propagator methods for calculating valence vertical ionization energies of Closed Shell molecules
Journal of Physical Chemistry A, 2015Co-Authors: H H Corzo, V G Zakrzewski, O Dolgounitcheva, Annia Galano, J V OrtizAbstract:Two accurate and computationally efficient electron-propagator (EP) methods for calculating the valence, vertical ionization energies (VIEs) of Closed–Shell molecules have been identified through comparisons with related approximations. VIEs of a representative set of Closed-Shell molecules were calculated with EP methods using 10 basis sets. The most easily executed method, the diagonal, second-order (D2) EP approximation, produces results that steadily rise as basis sets are improved toward values based on extrapolated coupled-cluster singles and doubles plus perturbative triples calculations, but its mean errors remain unacceptably large. The outer valence Green function, partial third-order and renormalized partial third-order methods (P3+), which employ the diagonal self-energy approximation, produce markedly better results but have a greater tendency to overestimate VIEs with larger basis sets. The best combination of accuracy and efficiency with a diagonal self-energy matrix is the P3+ approximatio...
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electron propagator calculations with nondiagonal partial fourth order self energies and unrestricted hartree fock reference states
International Journal of Quantum Chemistry, 2009Co-Authors: J V OrtizAbstract:The capabilities of a new electron propagator program, adapted for use with Gaussian 88, are described. Partial fourth-order self-energies in the diagonal (quasiparticle) approximation for Closed-Shell Hartree–Fock reference states are extended as follows. First, diagonal and nondiagonal self-energy matrices can now be calculated. Second, unrestricted as well as Closed-Shell Hartree–Fock reference states can be employed. Full second-order and third-order self-energies are also possible. Computational procedures are described and estimates are given for the number of operations required for the most difficult steps. One-electron pictures and quasiparticle models for open Shell systems are tested in calculations on the ionization energies of Cr− and CrH−2.
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an efficient renormalized self energy for calculating the electron binding energies of Closed Shell molecules and anions
International Journal of Quantum Chemistry, 2005Co-Authors: J V OrtizAbstract:The energy-dependent, nonlocal correlation potential known as the self- energy that appears in the Dyson equation has a pole and residue structure that enables renormalizations of its low-order, perturbative contributions to be estimated. The partial third-order (P3) approximation has been extensively applied to the ionization energies of Closed-Shell, organic molecules and is the most successful example of a low-order, self-energy method. A renormalization based on the P3 self-energy estimates higher- order contributions by scaling low-order terms that chiefly describe final-state relaxation. The resulting P3 self-energy retains the accuracy and efficiency of the P3 approximation, but also improves the latter method's performance with respect to the calculation of anion electron detachment energies without the introduction of adjustable parameters. An application to an anion that previously has yielded only to more intricate treatments of electron correlation demonstrates the power of this simple, new approximation. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem 105: 803- 808, 2005
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a nondiagonal renormalized extension of partial third order quasiparticle theory comparisons for Closed Shell ionization energies
Journal of Chemical Physics, 1998Co-Authors: J V OrtizAbstract:Valence ionization energies of a set Closed-Shell molecules calculated in a nondiagonal, renormalized approximation of the electron propagator have an average absolute error of 0.17 eV. This procedure extends the partial third order, quasiparticle approximation of J. Chem. Phys. 104, 7599 (1996) that has proven successful in many applications. Elements of the self-energy matrix include all second-order and many higher-order terms. Because of its fifth power dependence on basis set size and its independence from electron repulsion integrals with four virtual orbital indices, this method has considerable promise for large molecules. Formal and computational comparisons with renormalized electron propagator techniques that are complete through third-order illustrate the advantages of this procedure.
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Electron detachment energies of Closed-Shell anions calculated with a renormalized electron propagator
Chemical Physics Letters, 1998Co-Authors: J V OrtizAbstract: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.
Tor S. Bjørheim - One of the best experts on this subject based on the ideXlab platform.
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proton hydroxide ion and oxide ion affinities of Closed Shell oxides importance for the hydration reaction and correlation to electronic structure
Journal of Physical Chemistry C, 2020Co-Authors: Tor S. Bjørheim, Maximilian F Hoedl, Rotraut Merkle, Eugene A. Kotomin, Joachim MaierAbstract:Phenomenologically, the enthalpy of the dissociative water incorporation (hydration) of oxides is often found to be more favorable for more basic oxides. In the present work, we investigate proton, hydroxide ion, and oxide ion affinities (PA, HA, and OA) for 19 Closed-Shell oxides ranging from Li2O and Cs2O to TiO2, SnO2, and SiO2, including also perovskites such as SrTiO3 and BaZrO3 using first-principles defect calculations and thermochemical cycles. The proton affinity is found to play a predominant role in the hydration thermodynamics. The ion affinities are strongly correlated with the oxides’ electronic structure (specifically, the ionization potential (IP)). This intriguing correlation between PA and IP holds also for gaseous O species, suggesting a very general origin. Understanding the major factors controlling a metal oxide’s susceptibility for dissociative hydration of oxygen vacancies is not only of fundamental interest but also key to the successful development of novel mixed proton–electron ...
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proton hydroxide ion and oxide ion affinities of Closed Shell oxides importance for the hydration reaction and correlation to electronic structure
The Journal of Physical Chemistry, 2019Co-Authors: Tor S. Bjørheim, Maximilian F Hoedl, Rotraut Merkle, Eugene A. Kotomin, Joachim MaierAbstract:Phenomenologically, the enthalpy of the dissociative water incorporation (hydration) of oxides is often found to be more favorable for more basic oxides. In the present work, we investigate proton, hydroxide ion, and oxide ion affinities (PA, HA, and OA) for 19 Closed-Shell oxides ranging from Li₂O and Cs₂O to TiO₂, SnO₂, and SiO₂, including also perovskites such as SrTiO₃ and BaZrO₃ using first-principles defect calculations and thermochemical cycles. The proton affinity is found to play a predominant role in the hydration thermodynamics. The ion affinities are strongly correlated with the oxides’ electronic structure (specifically, the ionization potential (IP)). This intriguing correlation between PA and IP holds also for gaseous O species, suggesting a very general origin. Understanding the major factors controlling a metal oxide’s susceptibility for dissociative hydration of oxygen vacancies is not only of fundamental interest but also key to the successful development of novel mixed proton–electron conducting oxides for protonic ceramic fuel and electrolyzer cells. In addition to elucidating the hydration reaction, these ion affinities also serve a more general purpose, as they can be used to predict the oxides’ tendency to in-/excorporate a specific ion.