SAMOP 2023 – scientific programme

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MO: Fachverband Molekülphysik

MO 18: Cluster and Experimental Techniques (joint session MO/A)

MO 18.7: Talk

Thursday, March 9, 2023, 16:00–16:15, F142

Setup Of A Spectrometer To Detect Raman Optical Activity — •Klaus Hofmann and Ingo Fischer — Universität Würzburg, 97074 Würzburg, Germany

Raman Optical Activity (ROA) is a type of vibrational circular dichroism: chiral samples show different Raman intensities when utilizing circular polarized light. The ROA signal is very sensitive to the molecular geometry and environment of the sample, which can be analyzed by comparing the spectrum with quantum chemical calculations. ROA spectra exhibit high levels of noise and are prone to false signals, since the intensity difference is roughly 0.1% of the corresponding Raman peak.[1]

For this project, a Raman spectrometer was custom-built and modified to detect ROA. A modulation scheme repeatedly converts linear to right and left circular polarized light for excitation. Python was used to automate the experiment, data acquisition and post-processing. The beampath of the spectrometer and its implemented error reduction schemes[2] are shown. Post-processing is used to evaluate the signal. Literature known samples were measured to validate the spectrometer.

[1] V. Parchaňský, J. Kapitán, P. Bouř, RSC Adv. 2014, 4, 57125.

[2] W. Hug, Appl. Spectrosc. 2003, 57, 1.