## Abstract

A hierarchy of electronic structure calculations, scalings, and fittings were used to develop an analytic intermolecular potential for dimethyl methylphosphonate (DMMP) interacting with the TiO_{2} rutile (110) surface. The MP2/aug-cc-pVDZ (6-311+G* for Ti) level of theory, with basis set superposition error (BSSE) corrections, was used to calculate multiple intermolecular potential curves between TiO_{5}H_{6} as a model for the Ti and O atoms of the TiO_{2} surface, and CH_{3}OH and O - P(CH_{3})(OH)_{2} as models for different types of atoms comprising DMMP. Each intermolecular potential energy emphasized a particular atom-atom interaction, and the curves were fit simultaneously by a sum of two-body potentials between the atoms of the two interacting molecules. The resulting analytic intermolecular potential gives DMMP/TiO_{5}H _{6} potential curves in excellent agreement with those calculated using MP2/aug-cc-pVDZ (6-311+G* for Ti) theory. MP2 theory with the smaller basis set, 6-31++G* (6-31G* for Ti), gives DMMP/TiO _{5}H_{6} potential energy curves similar to those found using MP2/aug-cc-pVDZ (6-311+G* for Ti), suggesting the smaller basis set may be used to describe DMMP interactions with larger cluster models of the TiO _{2} surface. The TiO_{5}H_{6} cluster does not model either the 6-fold coordinated Ti atoms or the bridging O atoms of the TiO _{2} (110) surface, and to also model these atoms MP2/6-31++G* (6-31G* for Ti) theory was used to calculate potential energy curves for DMMP interacting with the larger Ti_{3}O_{13}H_{14} cluster and much large cluster Ti_{11}O_{40}H_{36} cluster. The two-body potential energy curves for DMMP/TiO_{5}H _{6} were scaled to fit both the DMMP/Ti_{3}O_{13}H _{14} and DMMP/Ti_{11}O_{40}H_{36} potential energy curves. The resulting parameters for the 5- and 6-fold coordinated Ti atoms and bridging and bulk O atoms were used to develop an analytic intermolecular potential for DMMP interacting with rutile TiO_{2} (110).

Original language | English |
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Pages (from-to) | 12403-12413 |

Number of pages | 11 |

Journal | Journal of Physical Chemistry C |

Volume | 115 |

Issue number | 25 |

DOIs | |

State | Published - Jun 30 2011 |