Theoretical assessment of the nuclear quantum effects on polymer crystallinity via perturbation theory and dynamics
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences. Computational Sciences and Engineering Division
- Univ. of South Carolina, Columbia, SC (United States). Dept. of Chemistry and Biochemistry
As seen in experiments with poly(3-hexylthiophene), substitution of hydrogen with deuterium on the main chain alone decreases crystallinity. To understand this effect, a general formalism for analysis of the dipole moments and polarizabilities incorporating quantum nuclei, is developed in this paper. The formalism, based on quantum dynamics of the proton/deuteron and on the perturbative analysis of the dipole interaction energy, accounts for the anharmonicity of a potential energy surface and for the anisotropy of molecular dipole moments. The formalism is implemented within the Discrete Variable Representation and the Density Functional Theory describing, respectively, the quantum proton/deuteron on the thiophene ring and the electronic structure of the 27-atom model polymer chain, embedded into a larger crystalline environment. Finally, the isotope effect is mainly attributed to the differences in the zero-point energy of the CH/CD bonds and to the isotope-dependence of the dipole-dipole inter-chain interactions.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Univ. of South Carolina, Columbia, SC (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC); National Science Foundation (NSF)
- Grant/Contract Number:
- AC05-00OR22725; ACI-1548562; CHE-1048629; CHE-1056188; CHE-1565985; OIA-1655740
- OSTI ID:
- 1474697
- Alternate ID(s):
- OSTI ID: 1472182
- Journal Information:
- International Journal of Quantum Chemistry, Vol. 118, Issue 20; ISSN 0020-7608
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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