Periodic Hartree-Fock study of siliceous mordenite

White, J C; Hess, A C

doi:10.1021/j100126a013

Title: Periodic Hartree-Fock study of siliceous mordenite

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Abstract

The authors report results of an all-electron ab initio periodic Hartree-Fock LCAO calculation on a completely dealuminated form of mordenite, Si[sub 48]O[sub 96], possessing Cmcm symmetry. The reported physical properties were computed using a modified 6-21G* basis. The resulting calculation is one of the largest ab initio studies carried out to date and demonstrates the feasibility of using ab initio methods to investigate large, complex systems. The sensitivity of the total crystal energy to small changes in geometry is explored by comparing the relative stabilities of seven reported experimental mordenite structures. The authors note that the larger the standard deviation in Si-O bond distances and O-Si-O angles the less energetically favorable the lattice will be. Crystal charge density and deformation density maps have been computed in the cylindrical channel of one of the reported crystal structures. Those calculations indicate the absence of charge density in the center of the channel ([approximately] 10[sup [minus]6] e/bohr[sup 3]) and a polarization of charge density localized near the oxygen atoms. Ab initio electrostatic potentials and electric fields in chemically important regions of the material have been computed from the Hartree-Fock ground state density. Comparisons of the ab initio electrostatic potential to those resulting frommore »« less

Authors:

White, J C; Hess, A C ^[1]

Pacific Northwest Lab., Richland, WA (United States)

Publication Date:: Thu Jun 17 00:00:00 EDT 1993

OSTI Identifier:: 6078136

DOE Contract Number:: AC06-76RL01830

Resource Type:: Journal Article

Journal Name:: Journal of Physical Chemistry; (United States)

Additional Journal Information:: Journal Volume: 97:24; Journal ID: ISSN 0022-3654

Country of Publication:: United States

Language:: English

Subject:: 36 MATERIALS SCIENCE; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; MORDENITE; CRYSTAL STRUCTURE; ELECTRONIC STRUCTURE; PHYSICAL PROPERTIES; CHARGE DENSITY; COMPUTERIZED SIMULATION; ELECTROSTATICS; HARTREE-FOCK METHOD; CALCULATION METHODS; INORGANIC ION EXCHANGERS; ION EXCHANGE MATERIALS; MATERIALS; MINERALS; SILICATE MINERALS; SIMULATION; ZEOLITES; 360202* - Ceramics, Cermets, & Refractories- Structure & Phase Studies; 360204 - Ceramics, Cermets, & Refractories- Physical Properties; 990200 - Mathematics & Computers

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                    White, J C, and Hess, A C. Periodic Hartree-Fock study of siliceous mordenite.  United States: N. p., 1993. 
        Web.  doi:10.1021/j100126a013.

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                    White, J C, & Hess, A C. Periodic Hartree-Fock study of siliceous mordenite.  United States.  https://doi.org/10.1021/j100126a013

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                    White, J C, and Hess, A C. 1993.  
        "Periodic Hartree-Fock study of siliceous mordenite".  United States.  https://doi.org/10.1021/j100126a013.

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@article{osti_6078136,

  title        = {Periodic Hartree-Fock study of siliceous mordenite},

  author       = {White, J C and Hess, A C},

  abstractNote = {The authors report results of an all-electron ab initio periodic Hartree-Fock LCAO calculation on a completely dealuminated form of mordenite, Si[sub 48]O[sub 96], possessing Cmcm symmetry. The reported physical properties were computed using a modified 6-21G* basis. The resulting calculation is one of the largest ab initio studies carried out to date and demonstrates the feasibility of using ab initio methods to investigate large, complex systems. The sensitivity of the total crystal energy to small changes in geometry is explored by comparing the relative stabilities of seven reported experimental mordenite structures. The authors note that the larger the standard deviation in Si-O bond distances and O-Si-O angles the less energetically favorable the lattice will be. Crystal charge density and deformation density maps have been computed in the cylindrical channel of one of the reported crystal structures. Those calculations indicate the absence of charge density in the center of the channel ([approximately] 10[sup [minus]6] e/bohr[sup 3]) and a polarization of charge density localized near the oxygen atoms. Ab initio electrostatic potentials and electric fields in chemically important regions of the material have been computed from the Hartree-Fock ground state density. Comparisons of the ab initio electrostatic potential to those resulting from model charge distributions (Mulliken point charges and formal point charges) are made. The point charge models investigated did not provide a quantitatively correct description of the electrostatics of these lattices. The average Mulliken charges are +2.09[vert bar]e[vert bar] and [minus]1.04[vert bar]e[vert bar] for silicon and oxygen, respectively. The total valence density of states and projected density of states condensed to all silicon and all oxygen atoms as well as projections into oxygen 2s and 2p orbitals have been evaluated. 47 refs., 8 figs., 1 tab.},

  doi          = {10.1021/j100126a013},

  url          = {https://www.osti.gov/biblio/6078136},
  journal      = {Journal of Physical Chemistry; (United States)},

  issn         = {0022-3654},

  number       = ,

  volume       = 97:24,

  place        = {United States},

  year         = {Thu Jun 17 00:00:00 EDT 1993},

  month        = {Thu Jun 17 00:00:00 EDT 1993}

}

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