|Title:||Modeling the conformation-specific infrared spectra of N-alkylbenzenes
|Author(s):||Tabor, Daniel P.
|Contributor(s):||Zwier, Timothy S.; Korn, Joseph A.; Hewett, Daniel M.; Sibert, Edwin
|Subject(s):||Conformers, isomers, chirality, stereochemistry
|Abstract:||Conformation-specific UV-IR double resonance spectra are presented for
n-alkylbenzenes. With the aid of a local
mode Hamiltonian that includes the effects of stretch-bend Fermi
coupling, the spectra of ethyl, n-propyl, and n-butylbenzene
are assigned to individual
These molecules allow for further development
of the work on a first principles method for calculating alkyl stretch spectra.
Due to the consistency of the anharmonic couplings from conformer to conformer, construction
of the model Hamiltonian for a given conformer only requires a harmonic frequency
calculation at the conformer's minimum geometry as an input. The model Hamiltonian can be parameterized with either
density functional theory or MP2 electronic structure calculations. The
relative strengths and weaknesses of these methods are evaluated, including
their predictions of the relative energetics of the conformers.
Finally, the IR spectra for conformers that have the alkyl chain bend back and interact with
the $\pi$ cloud of the benzene ring are modeled.
|Publisher:||International Symposium on Molecular Spectroscopy
|Rights Information:||Copyright 2016 by the authors
|Date Available in IDEALS:||2016-08-22