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Design and Implementation of Quantum Chemistry Methods for the Condensed Phase: Noncovalent Interactions at the Nanoscale and Excited States in Bulk Solution

Carter-Fenk, Kevin D
http://orcid.org/0000-0001-8302-4750
http://rave.ohiolink.edu/etdc/view?acc_num=osu161617640330551

Abstract Details

2021, Doctor of Philosophy, Ohio State University, Chemistry.
The computational bottleneck of applying quantum chemistry methods has always been a significant obstacle to calculating the properties of condensed-phase systems. In this work we present accurate, scalable methods that push the dynamic range of ground- and excited-state quantum chemistry into the condensed-phase. First, we introduce an extension of symmetry-adapted perturbation theory that includes nonadditive (many-atom) dispersion effects that are essential in the description of large systems. Application of this approach to the study of π-π interactions has revealed that the dominant paradigm (based on low-order electrostatic multipoles) for understanding π-stacking is fundamentally flawed. We propose a reformulation of the electrostatic model of aromatic π-π interactions that is based on van der Waals forces, instead. Our work with π-stacking is exemplary of the utility that symmetry-adapted perturbation theory with many-body dispersion (SAPT+MBD) has as an interpretive tool, and our results suggest that it will be extremely useful in characterizing intermolecular interactions at the nanoscale. In the second part of this work, we introduce several efficient methods for solution-phase photochemistry. Contributions of this work include the implementation of a vibrational exciton model, a new root-homing algorithm based on level shifting, and introducing natural charge-transfer orbitals to combat spurious states in solution-phase time-dependent density functional theory (TDDFT). The vibrational exciton model is extremely scalable, and we use it to investigate the infrared spectrum of >200 surfactant molecules at the air/water interface. Our results have lead to insights into the nature of signal depletion in one-dimensional infrared spectra of self-aggregating molecules at interfaces. Our root-homing algorithm is robust to variational collapse, and shows promise in finding orbital-optimized excited states when the density of states becomes large. Lastly, our natural charge-transfer analysis protocol allows for TDDFT calculations on solvated chromophores with hundreds of explicit solvent molecules. Altogether, these tools will serve to promote investigations into the properties of photochemistry in solution that were simply impossible in the past.
John Herbert (Advisor)
Heather Allen (Committee Member)
Sherwin Singer (Committee Member)
Barbara Ryden (Committee Member)
295 p.
Physical Chemistry
symmetry-adapted perturbation theory; intermolecular; noncovalent; pi-stacking; pi-pi; photochemistry; excited states; time-dependent density functional theory; TDDFT; solution phase; condensed phase; ab initio; quantum chemistry; electronic structure

Recommended Citations

Citations

  • Carter-Fenk, K. D. (2021). Design and Implementation of Quantum Chemistry Methods for the Condensed Phase: Noncovalent Interactions at the Nanoscale and Excited States in Bulk Solution [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu161617640330551

    APA Style (7th edition)

  • Carter-Fenk, Kevin. Design and Implementation of Quantum Chemistry Methods for the Condensed Phase: Noncovalent Interactions at the Nanoscale and Excited States in Bulk Solution. 2021. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu161617640330551.

    MLA Style (8th edition)

  • Carter-Fenk, Kevin. "Design and Implementation of Quantum Chemistry Methods for the Condensed Phase: Noncovalent Interactions at the Nanoscale and Excited States in Bulk Solution." Doctoral dissertation, Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu161617640330551

    Chicago Manual of Style (17th edition)

osu161617640330551
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