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Updated: Oct 8, 2025

Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers
Published on: August 18, 2017
Strong ortho/para effects in the vibrational spectrum of Cl-(H2)
Franziska Dahlmann1, Christine Lochmann1, Aravindh N Marimuthu2
1Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Technikerstraße 25, 6020 Innsbruck, Austria.
Abstract:
The predissociation spectrum of the Cl-35(H2) complex is measured between 450 and 800 cm-1 in a multipole radiofrequency ion trap at different temperatures using the FELIX infrared free electron laser. Above a certain temperature, the removal of the Cl-(p-H2) para nuclear spin isomer by ligand exchange to the Cl-(o-H2) ortho isomer is suppressed effectively, thereby making it possible to detect the spectrum of this more weakly bound complex. At trap temperatures of 30.5 and 41.5 K, we detect two vibrational bands of Cl-(p-H2) at 510(1) and 606(1) cm-1. Using accurate quantum calculations, these bands are assigned to transitions to the inter-monomer vibrational modes (v1,v2 l2 ) = (0, 20) and (1, 20), respectively.
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