The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Isaiah Shavitt - One of the best experts on this subject based on the ideXlab platform.
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comparison of theoretical methods for the determination of the Protonation and deProtonation energies of nh sub 3 h sub 2 o hf ph sub 3 h sub 2 s hcl and hcn
The Journal of Physical Chemistry, 1990Co-Authors: J E Del Bene, Isaiah ShavittAbstract:The structures of the bases NH{sub 3}, H{sub 2}O, HF, PH{sub 3}, H{sub 2}S, HCl, and HCN and the corresponding protonated and deprotonated ions have been optimized by using second-order Moller-Plesset perturbation theory with the 6-31+G(d,p) basis. Basis set superposition errors for computed Protonation and deProtonation energies of NH{sub 3} were evaluated for four different basis sets. Single-point calculations on all species were performed with the 6-31+G(2d,2p) basis using the following correlation methods: many-body (Moller-Plesset) perturbation theory at second (MP2), third (MP3), and fourth (MP4) order; the linearized coupled-cluster method (LCCM); the averaged coupled-pair functional (ACPF); configuration interaction with all single and double excitations (CISD); and CISD with the Davidson and the Pople corrections, all relative to a single-reference Hartree-Fock function.
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comparison of theoretical methods for the determination of the Protonation and deProtonation energies of nh3 h2o hf ph3 h2s hcl and hcn
The Journal of Physical Chemistry, 1990Co-Authors: J E Del Bene, Isaiah ShavittAbstract:The structures of the bases NH 3 , H 2 O, HF, PH 3 , H 2 S, HCl, and HCN and the corresponding protonated and deprotonated ions have been optimized by using second-order MOller-Plesset perturbation theory with the 6-31+G(d,p) basis. Basis set superposition errors for computed Protonation and deProtonation energies of NH 3 were evaluated for four different basis sets. Single-point calculations on all species were performed with the 6-31+G(2d,2p) basis using the following correlation methods: many-body (MOller-Plesset) perturbation theory at second (MP2), third (MP3), and fourth (MP4) order; the linearized coupled-cluster method (LCCM); the averaged coupled-pair functional (ACPF); configuration interaction with all single and double excitations (CISD); and CISD with the Davidson and the Pople corrections, all relative to a single-reference hartree-Fock function
L. Zhang - One of the best experts on this subject based on the ideXlab platform.
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Structures and charging of alpha-alumina (0001)/water interfaces studies by sum-frequency vibrational spectroscopy - eScholarship
2009Co-Authors: L. ZhangAbstract:Page 1 of 32 Structures and Charging of -Alumina (0001)/Water Interfaces Studied by Sum-Frequency Vibrational Spectroscopy Luning Zhang, † Chuanshan Tian, † Glenn A. Waychunas, ‡ and Y. Ron Shen,* ,† Department of Physics, University of California, Berkeley, CA 94720, and Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 Abstract: Sum-frequency vibrational spectroscopy in the OH stretch region was employed to study structures of water/ -Al 2 O 3 (0001) interfaces at different pH values. Observed spectra indicate that Protonation and deProtonation of the alumina surface dominate at low and high pH, respectively, with the interface positively and negatively charged accordingly. The point of zero charge (p.z.c.) appears at pH ~6.3, which is close to the values obtained from streaming potential and second harmonic generation studies. It is significantly lower than the p.z.c. of alumina powder. The result can be understood from the pK values of Protonation and deProtonation at the water/ -Al 2 O 3 (0001) interface. The p.z.c. of amorphous alumina was found to be similar to that of powder alumina. * Corresponding author. E-mail: yrshen@berkeley.edu. Fax (510) 643 8923. † University of California. ‡ Lawrence Berkeley National Laboratory. ACS Paragon Plus Environment
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Structures and charging of alpha-alumina (0001)/water interfaces studies by sum-frequency vibrational spectroscopy
Journal of the American Chemical Society, 2008Co-Authors: L. Zhang, C. Tian, Glenn A. Waychunas, Y. R. ShenAbstract:Sum-frequency vibrational spectroscopy in the OH stretch region was employed to study structures of water/α-Al2O3 (0001) interfaces at different pH values. Observed spectra indicate that Protonation and deProtonation of the alumina surface dominate at low and high pH, respectively, with the interface positively and negatively charged accordingly. The point of zero charge (pzc) appears at pH ≈ 6.3, which is close to the values obtained from streaming potential and second-harmonic generation studies. It is significantly lower than the pzc of alumina powder. The result can be understood from the pK values of Protonation and deProtonation at the water/α-Al2O3 (0001) interface. The pzc of amorphous alumina was found to be similar to that of powder alumina.
Asit K Chandra - One of the best experts on this subject based on the ideXlab platform.
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Protonation and deProtonation energies of uracil implications for the uracil water complex
Journal of the Chemical Society Faraday Transactions, 1998Co-Authors: Minh Tho Nguyen, Asit K ChandraAbstract:The proton affinities PA(B) of the four oxygen lone pairs and of the two nitrogen atoms and the deProtonation energies PA(A-) of the two NH bonds of uracil are calculated by density functional theory (DFT) using the 6-31G(d,p) and 6-31G++(d,p) basis set. The PAs are also calculated by abinitio MO theory (MP4) using 6-31G(d,p) for comparison. The DFT/B3LYP energies and the frequency shifts of the ν(OH) stretching vibrations are calculated with the 6-31++G(d,p) basis for the three cyclic structures of the uracil–water complexes. The usual correlations between energies of frequency shifts and the PAs do not hold in the case of closed structures. The most stable cyclic complex is formed at the oxygen lone pair characterized by the lowest basicity and at the NH bond characterized by the highest acidity. The energy of the complex decreases with increasing value of the difference PA(A-)-PA(B).
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Protonation and deProtonation energies of uracil Implications for the uracil–water complex
Journal of the Chemical Society Faraday Transactions, 1998Co-Authors: Minh Tho Nguyen, Asit K ChandraAbstract:The proton affinities PA(B) of the four oxygen lone pairs and of the two nitrogen atoms and the deProtonation energies PA(A-) of the two NH bonds of uracil are calculated by density functional theory (DFT) using the 6-31G(d,p) and 6-31G++(d,p) basis set. The PAs are also calculated by abinitio MO theory (MP4) using 6-31G(d,p) for comparison. The DFT/B3LYP energies and the frequency shifts of the ν(OH) stretching vibrations are calculated with the 6-31++G(d,p) basis for the three cyclic structures of the uracil–water complexes. The usual correlations between energies of frequency shifts and the PAs do not hold in the case of closed structures. The most stable cyclic complex is formed at the oxygen lone pair characterized by the lowest basicity and at the NH bond characterized by the highest acidity. The energy of the complex decreases with increasing value of the difference PA(A-)-PA(B).
Shu Yamaguchi - One of the best experts on this subject based on the ideXlab platform.
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direct observation of redox state modulation at carbon amorphous tantalum oxide thin film hetero interface probed by means of in situ hard x ray photoemission spectroscopy
Solid State Ionics, 2013Co-Authors: Takashi Tsuchiya, Shogo Miyoshi, Yoshiyuki Yamashita, Hideki Yoshikawa, Kazuya Terabe, Keisuke Kobayashi, Shu YamaguchiAbstract:Abstract A hard X-ray photoelectron spectroscopy (HX-PES) has been employed in order to investigate electrochemical polarization at carbon/amorphous tantalum oxide thin film hetero-interface. In situ HX-PES observation of Ta 4 f and O 1 s spectra has revealed parallel chemical shift of the core levels within the redox window width of 2.4 eV, indicating Fermi level shifts due to the redox state modulation mediated by Protonation and deProtonation under applied dc bias voltage. In addition to protons, oxide ions are suggested to take part in the redox state variation especially under a larger applied electric field. The results have been discussed in framework of solid state electrochemistry and Pourbaix-type E -pO diagram to indicate electrochemical stability domains of solid oxide systems is proposed.
J E Del Bene - One of the best experts on this subject based on the ideXlab platform.
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comparison of theoretical methods for the determination of the Protonation and deProtonation energies of nh sub 3 h sub 2 o hf ph sub 3 h sub 2 s hcl and hcn
The Journal of Physical Chemistry, 1990Co-Authors: J E Del Bene, Isaiah ShavittAbstract:The structures of the bases NH{sub 3}, H{sub 2}O, HF, PH{sub 3}, H{sub 2}S, HCl, and HCN and the corresponding protonated and deprotonated ions have been optimized by using second-order Moller-Plesset perturbation theory with the 6-31+G(d,p) basis. Basis set superposition errors for computed Protonation and deProtonation energies of NH{sub 3} were evaluated for four different basis sets. Single-point calculations on all species were performed with the 6-31+G(2d,2p) basis using the following correlation methods: many-body (Moller-Plesset) perturbation theory at second (MP2), third (MP3), and fourth (MP4) order; the linearized coupled-cluster method (LCCM); the averaged coupled-pair functional (ACPF); configuration interaction with all single and double excitations (CISD); and CISD with the Davidson and the Pople corrections, all relative to a single-reference Hartree-Fock function.
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comparison of theoretical methods for the determination of the Protonation and deProtonation energies of nh3 h2o hf ph3 h2s hcl and hcn
The Journal of Physical Chemistry, 1990Co-Authors: J E Del Bene, Isaiah ShavittAbstract:The structures of the bases NH 3 , H 2 O, HF, PH 3 , H 2 S, HCl, and HCN and the corresponding protonated and deprotonated ions have been optimized by using second-order MOller-Plesset perturbation theory with the 6-31+G(d,p) basis. Basis set superposition errors for computed Protonation and deProtonation energies of NH 3 were evaluated for four different basis sets. Single-point calculations on all species were performed with the 6-31+G(2d,2p) basis using the following correlation methods: many-body (MOller-Plesset) perturbation theory at second (MP2), third (MP3), and fourth (MP4) order; the linearized coupled-cluster method (LCCM); the averaged coupled-pair functional (ACPF); configuration interaction with all single and double excitations (CISD); and CISD with the Davidson and the Pople corrections, all relative to a single-reference hartree-Fock function
