Erlangen 2022 – scientific programme

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MO: Fachverband Molekülphysik

MO 15: Poster 2

MO 15.1: Poster

Wednesday, March 16, 2022, 16:30–18:30, P

Multiple-Quantum Two-Dimensional Fluorescence Spectroscopy of a Squaraine Polymer — •Ajay Jayachandran, Stefan Müller, and Tobias Brixner — Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg

Molecular aggregates such as squaraine heteropolymers feature a manifold of multiexcitonic states [1]. These multiexcitonic states are a result of numerous electronically coupled heterochromophoric units. However, it is challenging to investigate the correlations and spectral properties of the states of a particular multiexciton manifold using conventional spectroscopic tools due to convolution with spectral signatures of singly excited states. Here we make use of advances in fluorescence-based multidimensional spectroscopy to selectively measure multi-quantum correlations by using phase-cycled pulse sequences in a collinear excitation geometry [2]. Spectrally resolved two-quantum and three-quantum coherence signatures are captured through fourth-order and sixth-order signals which are acquired using a 36-fold phase-cycling scheme of a three-pulse excitation sequence. We also examine the eighth-order signals which can be resolved by using 64-fold phase cycling to observe correlations with four- quantum coherences without signal aliasing.

[1] S. F. Völker et al., J. Phys. Chem. C. 118, 17467 (2014).

[2] S. Draeger et al., Opt. Express 25, 3259 (2017).