### Abstract

A model compound was chosen to see whether it mimics a backbone of an amino acid residue in a peptide structure so that a model Ramachandran potential energy surface could be fitted by a mathematical function. A Fourier series of two independent variables (ψ and ψ) has been used to fit a set of grid points representing the surface. To determine the accuracy of the fitted equation vs. the generated data points three grids were examined, 24 ^{2}=576 points (15° intervals), 12^{2}=144 points (30° intervals), and 6^{2}=36 points (60° intervals). The grid points were generated for the S enantiomer and a Fourier expansion was fitted to the grid points along with a functional analysis of each fitted expansion. A series of functions were found for 15, 30, and 60° increments in order to see the lowest limit of resolution of the grid needed for a relatively accurate fit. Ab initio calculations were also carried out for the R and S enantiomer to fit a 31 term Fourier expansion where a functional analysis determined the location of the critical points from the expansions. Geometry optimizations were preformed to locate more precisely the minima. The optimized minima were then included in a new surface that was fit.

Original language | English |
---|---|

Pages (from-to) | 79-87 |

Number of pages | 9 |

Journal | Journal of Molecular Structure: THEOCHEM |

Volume | 666-667 |

DOIs | |

Publication status | Published - Dec 29 2003 |

### Fingerprint

### Keywords

- Double rotor
- Fourier expansion
- Functional analysis
- Geometry optimization
- Minimum energy conformer
- Potential energy surface

### ASJC Scopus subject areas

- Physical and Theoretical Chemistry
- Computational Theory and Mathematics
- Atomic and Molecular Physics, and Optics

### Cite this

*Journal of Molecular Structure: THEOCHEM*,

*666-667*, 79-87. https://doi.org/10.1016/j.theochem.2003.08.015

**The fitting and functional analysis of a double rotor potential energy surface for the R and S enantiomers of 1-chloro-3-fluoro-isobutane.** / Kehoe, Tara A K; Peterson, Mike R.; Chass, Gregory A.; Viskolcz, B.; Stacho, Laszlo; Csizmadia, I.

Research output: Contribution to journal › Article

*Journal of Molecular Structure: THEOCHEM*, vol. 666-667, pp. 79-87. https://doi.org/10.1016/j.theochem.2003.08.015

}

TY - JOUR

T1 - The fitting and functional analysis of a double rotor potential energy surface for the R and S enantiomers of 1-chloro-3-fluoro-isobutane

AU - Kehoe, Tara A K

AU - Peterson, Mike R.

AU - Chass, Gregory A.

AU - Viskolcz, B.

AU - Stacho, Laszlo

AU - Csizmadia, I.

PY - 2003/12/29

Y1 - 2003/12/29

N2 - A model compound was chosen to see whether it mimics a backbone of an amino acid residue in a peptide structure so that a model Ramachandran potential energy surface could be fitted by a mathematical function. A Fourier series of two independent variables (ψ and ψ) has been used to fit a set of grid points representing the surface. To determine the accuracy of the fitted equation vs. the generated data points three grids were examined, 24 2=576 points (15° intervals), 122=144 points (30° intervals), and 62=36 points (60° intervals). The grid points were generated for the S enantiomer and a Fourier expansion was fitted to the grid points along with a functional analysis of each fitted expansion. A series of functions were found for 15, 30, and 60° increments in order to see the lowest limit of resolution of the grid needed for a relatively accurate fit. Ab initio calculations were also carried out for the R and S enantiomer to fit a 31 term Fourier expansion where a functional analysis determined the location of the critical points from the expansions. Geometry optimizations were preformed to locate more precisely the minima. The optimized minima were then included in a new surface that was fit.

AB - A model compound was chosen to see whether it mimics a backbone of an amino acid residue in a peptide structure so that a model Ramachandran potential energy surface could be fitted by a mathematical function. A Fourier series of two independent variables (ψ and ψ) has been used to fit a set of grid points representing the surface. To determine the accuracy of the fitted equation vs. the generated data points three grids were examined, 24 2=576 points (15° intervals), 122=144 points (30° intervals), and 62=36 points (60° intervals). The grid points were generated for the S enantiomer and a Fourier expansion was fitted to the grid points along with a functional analysis of each fitted expansion. A series of functions were found for 15, 30, and 60° increments in order to see the lowest limit of resolution of the grid needed for a relatively accurate fit. Ab initio calculations were also carried out for the R and S enantiomer to fit a 31 term Fourier expansion where a functional analysis determined the location of the critical points from the expansions. Geometry optimizations were preformed to locate more precisely the minima. The optimized minima were then included in a new surface that was fit.

KW - Double rotor

KW - Fourier expansion

KW - Functional analysis

KW - Geometry optimization

KW - Minimum energy conformer

KW - Potential energy surface

UR - http://www.scopus.com/inward/record.url?scp=1642451869&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=1642451869&partnerID=8YFLogxK

U2 - 10.1016/j.theochem.2003.08.015

DO - 10.1016/j.theochem.2003.08.015

M3 - Article

AN - SCOPUS:1642451869

VL - 666-667

SP - 79

EP - 87

JO - Computational and Theoretical Chemistry

JF - Computational and Theoretical Chemistry

SN - 2210-271X

ER -