Freiburg 2024 – wissenschaftliches Programm

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MO: Fachverband Molekülphysik

MO 23: Poster: Chirality

MO 23.5: Poster

Donnerstag, 14. März 2024, 17:00–19:00, Tent C

Experimental setup to study enhancement of circular dichroism in ion yield of 3-methyl cyclopentanone via tailored femtosecond laser pulses — •Sagnik Das, Jayanta Ghosh, Sudheendran Vasudevan, Hangyeol Lee, Nicolas Ladda, Simon Ranecky, Tonio Rosen, Till Stehling, Fabian Westmeier, Arne Senftleben, Thomas Baumert, and Hendrike Braun — Institut für Physik, Universität Kassel

Femtosecond laser pulses were employed to ionize 3-methyl cyclopentanone (3-MCP) in the home-built time-of-flight mass spectrometer. A ‘twin peak’ measurement technique [1] was utilized, to obtain ion yields from left and right circularly polarised laser pulses in the same laser shot. Such a technique reduces the statistical error of measurement and allows for simultaneous chirp compensation in both left and right-handed light. Circular dichroism in ion yield (CDIY) is the difference in ion yield from the left and right circularly polarised light for a given enantiomer [2,3]. Switching the enantiomer, the sign of CDIY is flipped. At the wavelengths where we performed the experiments, a 1+1+1 resonance-enhanced multiphoton ionization in 3-MCP takes place via the π^* ← n band, which exhibits a strong circular dichroism. It was found that linear chirp enhances the CDIY. We systematically investigated the reason behind the enhancement of CDIY for chirped pulses.

[1] T. Ring et al., Rev. Sci. Instrum., 92, 033001, 2021

[2] U. Boesl and A. Bornschlegl, ChemPhysChem, 7, 2085, 2006

[3] H. G. Breunig et al., ChemPhysChem, 10, 1199, 2009

Keywords: chirality; femtosecond; coherent control; circular dichroism; femtosecond spectroscopy