Far-IR spectroscopy of neutral gas phase peptides: signatures from combined experiments and simulations

Mahé, Jérôme

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https://hdl.handle.net/2142/91115 Copy

Description

Title

Far-IR spectroscopy of neutral gas phase peptides: signatures from combined experiments and simulations

Author(s)

Mahé, Jérôme

Contributor(s)

• Rijs, Anouk
• Jaeqx, Sander
• Bakker, Daniël
• Gaigeot, Marie-Pierre

Issue Date

2016-06-21

Keyword(s)

Spectroscopy of Large Amplitude Motions

Abstract

Within the past two decades, action vibrational spectroscopy has become an almost routine experimental method to probe the structures of molecules and clusters in the gas phase (neutral and ions). Such experiments are mainly performed in the 1000-4000 $\wn$ fingerprint regions. Though successful in many respects, these spectral domains can be however restrictive in the information provided, and sometimes reach limitations for unravelling structures without ambiguity. In a collaborative work with the group of Dr A.M. Rijs (FELIX laboratory, Radbout University, The Netherlands) we have launched a new strategy where the far-IR/Tera-Hertz domain (100-800 $\wn$ domain) is experimentally probed for neutral gas phase molecules. Our group in Paris apply finite temperature DFT-based molecular dynamics (DFT-MD) simulations in order to unravel the complex signatures arising in the far-IR domain, and provide an unambiguous assignment both of the structural conformation of the gas phase molecules (taking into account the experimental conditions) and an understanding of the spectral signatures/fingerprints. We will discuss our experimental and theoretical investigations on two neutral peptides in the 100-800 $\wn$ far-IR spectral domain, i.e. Z-Ala$_{6}$ and PheGly dipeptide, that represent two systems which definitive conformational assignment was not possible without the far IR signatures. We will also present our very recent results on the Phe-X peptide series, where X stands for Gly, Ala, Pro, Val, Ser, Cys, combining experiments and DFT-MD simulations, providing a detailed understanding of the vibrational fingerprints in the far-IR domain. In all exemples, we will show how DFT-MD simulations is the proper theoretical tool to account for vibrational anharmonicities and mode couplings, of prime importance in the far-IR domain. References : J. Mah\'{e}, S. Jaeqx, A.M. Rijs, M.P. Gaigeot, Phys. Chem. Chem. Phys., 17 :25905 (2015) \\ \hspace{1 cm} S. Jaeqx, J. Oomens, A. Cimas, M.P. Gaigeot, A.M. Rijs, Angew. Chemie. Int., 53 :3663 (2014)

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

En

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http://hdl.handle.net/2142/91115

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Copyright 2016 by the authors

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