Berlin 2014 – scientific programme
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MO: Fachverband Molekülphysik
MO 5: Posters 1: Electronic Spectroscopy, Photochemistry, Femtosecond Spectroscopy
MO 5.2: Poster
Monday, March 17, 2014, 16:30–18:30, Spree-Palais
Two Photon Excitation Spectroscopy on Terrylene — •Tobias Staut and Gregor Jung — Biophysical Chemistry, Saarland University, Saarbrücken, Germany
Due to its excellent photostability, extinction coefficient and quantum yield, Terrylene is ideally suited for single-molecule experiments. Yet, as Terrylene is relatively rare and expensive, its chemical and nonlinear optical properties are mostly unexplored. In order to prepare further examinations we successfully assembled a two photon excitation (2PE) fluorescence spectrometer. Instead of single point measurements to acquire absolute values of the absorptivity σ2PE, we use the slope of the fluorescence intensity versus the varying excitation intensity. Our setup with a pulsed Ti:Sa excitation laser allows measurements in the wavelength range from 750 nm to 860 nm. The symmetry of excited states can be determined by comparing different laser light polarizations to each other. The reliability of our measured absolute absorptivities was verified by a comparison of σ2PE of Fluorescein, Rhodamine 6G, and Perylene with published results. In our setup, two different states of Terrylene in solution can be excited by 2PE. As a first step towards the single-molecule level we measured single point spectra of Terrylene in p-Terphenyl with a cw Ti:Sa excitation laser. Further experiments will include spectroscopic measurements on the single-molecule level in order to determine the 2PE tensor.