### Abstract

The potential energy of the infinite periodic chain model of polyacetylene (pPA) is symmetric with two equivalent minima separated by the Peierls' stabilization barrier. In this work it is shown how an energy scale and vibrational energy levels for this highly anharmonic Peierls' degree of freedom can be estimated. Particular attention is given to the potential energy increase for large deformations. Two empirical methods and direct periodic boundary condition (PBC) density functional theory (DFT) calculations are in semi-quantitative agreement with each other. Each lead to the conclusion that pPA has a zero-point level that is above the Peierls' barrier. The argument does not depend critically on the barrier height or the other parameters of the model or the computation method. It is concluded that pPA will not exhibit bond alternation since two stable structures are not possible due primarily to the stiffness of the underlying CC sigma bond system.

Original language | English (US) |
---|---|

Pages (from-to) | 78-82 |

Number of pages | 5 |

Journal | Journal of Molecular Structure |

Volume | 1032 |

DOIs | |

State | Published - Jan 30 2013 |

### Fingerprint

### Keywords

- Bond length alternation
- Peierls' instability
- Polyacetylene structure
- Zero-point level

### ASJC Scopus subject areas

- Spectroscopy
- Analytical Chemistry
- Inorganic Chemistry
- Organic Chemistry

### Cite this

*Journal of Molecular Structure*,

*1032*, 78-82. https://doi.org/10.1016/j.molstruc.2012.07.051

**Bond alternation in infinite periodic polyacetylene : Dynamical treatment of the anharmonic potential.** / Hudson, Bruce S; Allis, Damian G.

Research output: Contribution to journal › Article

*Journal of Molecular Structure*, vol. 1032, pp. 78-82. https://doi.org/10.1016/j.molstruc.2012.07.051

}

TY - JOUR

T1 - Bond alternation in infinite periodic polyacetylene

T2 - Dynamical treatment of the anharmonic potential

AU - Hudson, Bruce S

AU - Allis, Damian G.

PY - 2013/1/30

Y1 - 2013/1/30

N2 - The potential energy of the infinite periodic chain model of polyacetylene (pPA) is symmetric with two equivalent minima separated by the Peierls' stabilization barrier. In this work it is shown how an energy scale and vibrational energy levels for this highly anharmonic Peierls' degree of freedom can be estimated. Particular attention is given to the potential energy increase for large deformations. Two empirical methods and direct periodic boundary condition (PBC) density functional theory (DFT) calculations are in semi-quantitative agreement with each other. Each lead to the conclusion that pPA has a zero-point level that is above the Peierls' barrier. The argument does not depend critically on the barrier height or the other parameters of the model or the computation method. It is concluded that pPA will not exhibit bond alternation since two stable structures are not possible due primarily to the stiffness of the underlying CC sigma bond system.

AB - The potential energy of the infinite periodic chain model of polyacetylene (pPA) is symmetric with two equivalent minima separated by the Peierls' stabilization barrier. In this work it is shown how an energy scale and vibrational energy levels for this highly anharmonic Peierls' degree of freedom can be estimated. Particular attention is given to the potential energy increase for large deformations. Two empirical methods and direct periodic boundary condition (PBC) density functional theory (DFT) calculations are in semi-quantitative agreement with each other. Each lead to the conclusion that pPA has a zero-point level that is above the Peierls' barrier. The argument does not depend critically on the barrier height or the other parameters of the model or the computation method. It is concluded that pPA will not exhibit bond alternation since two stable structures are not possible due primarily to the stiffness of the underlying CC sigma bond system.

KW - Bond length alternation

KW - Peierls' instability

KW - Polyacetylene structure

KW - Zero-point level

UR - http://www.scopus.com/inward/record.url?scp=84865470536&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84865470536&partnerID=8YFLogxK

U2 - 10.1016/j.molstruc.2012.07.051

DO - 10.1016/j.molstruc.2012.07.051

M3 - Article

AN - SCOPUS:84865470536

VL - 1032

SP - 78

EP - 82

JO - Journal of Molecular Structure

JF - Journal of Molecular Structure

SN - 0022-2860

ER -