Spectroscopic characterization of isomerization transition states

Baraban, Joshua H.

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https://hdl.handle.net/2142/91158 Copy

Description

Title

Spectroscopic characterization of isomerization transition states

Author(s)

Baraban, Joshua H.

Contributor(s)

• Field, Robert W.
• Merer, Anthony
• Stanton, John F.
• Mellau, Georg Ch.
• Changala, Bryan

Issue Date

2016-06-20

Keyword(s)

Spectroscopy of Large Amplitude Motions

Abstract

Transition state theory is central to our understanding of chemical reaction dynamics. We demonstrate here a method for extracting transition state energies and properties from a characteristic pattern found in frequency domain spectra of isomerizing systems. This pattern, a dip in the spacings of certain barrier-proximal vibrational levels, can be understood using the concept of effective frequency, $\omega^{\mathrm{eff}}$. The method is applied to the \textit{cis}-\textit{trans} conformational change in the S$_1$ state of C$_{2}$H$_{2}$ and the bond-breaking HCN-HNC isomerization. In both cases, the barrier heights derived from spectroscopic data agree extremely well with previous \textit{ab initio} calculations. We also show that it is possible to distinguish between vibrational modes that are actively involved in the isomerization process and those that are passive bystanders. (This work has been published in J.~H.~Baraban, P.~B.~Changala, G.~Ch.~Mellau, J.~F.~Stanton, A.~J.~Merer, and R.~W.~Field. Spectroscopic characterization of isomerization transition states. {\em Science}, 350(6266):1338--1342, 2015.)

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

En

Permalink

http://hdl.handle.net/2142/91158

Copyright and License Information

Copyright 2016 by the authors

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