Zeitaufgelöste Photoelektronen und Photoionen Spektroskopie organischer Moleküle und Komplexe (TR-PEPICO)

In this project, we are studying the dynamics of isolated molecules and molecular complexes. The main goal of this project is to study effects on the excitation dynamics of molecular systems that are caused by the molecular environment. The presence of molecular neighbors creates relaxation pathways that do not exist for isolated molecules such as charge or energy transfer processes as well as hydrogen or proton transfer reactions between two neighboring molecules. One future goal of the project is to study electron-coupled proton-transfer reactions between organic chromophores and water molecules that are of high relevance for the field of photocatalytic water splitting.

The study of small molecular clusters instead of bulk solutions or solids to elucidate these processes allows the application of photoelectron and photoion imaging and limits negative effects caused by condensed environments. Photoelectron spectroscopy is a very direct probe of the electronic structure and dynamics and electron imaging techniques in particular can provide additional information on the involved orbitals or in the case of chiral molecules. To enhance the information obtained in our experiments we are actively working on extending the photon energies available for ionization into the extreme ultraviolet (XUV), improve the experimental time-resolution and implement the detection of electrons and ions in coincidence.

Foto Labor Annex 1 — Photograph of the experimental setup consisting of a cluster beam source, an electron velocity map imaging (VMI) spectrometer and an ion mass spectrometer.

Electron-VMI resulting from the resonance-enhanced ionization of potassium atoms. — Electron-VMI resulting from the resonance-enhanced multiphoton ionization of potassium atoms.

Relevante Publikationen:

[24] A. Scognamiglio, K. S. Thalmann, S. Hartweg, et al.:
Non-adiabatic electronic relaxation of tetracene from its brightest singlet excited state
J. Chem. Phys., 2024, 161 (2), 024302-1-024302-10

[23] N. Rendler, A. Scognamiglio, M. Barranco, et al.:
Dynamics of Photoexcited Cs Atoms Attached to Helium Nanodroplets
J. Phys. Chem. A, 2021, 125, (41), 9048–9059

[22] F. Coppens, J. v. Vangerow, A. Leal, et al.:
Fall-back time for photo-ionized Cs atoms attached to superfluid ⁴He nanodroplets
Eur. Phys. J. D, 2019, 73 (94), (-8pp)

[21] N. V. Dozmorov, A. V. Baklanov, J. v. Vangerow, et al.:
Quantum dynamics of Rb atoms desorbing off the surface of He nanodroplets
Phys. Rev. A, 2018, 98 (4), 043403-1-043403-9

[20] F. Coppens, J. v. Vangerow, M. Barranco, et al.:
Desorption dynamics of RbHe exciplexes off He nanodroplets induced by spin-relaxation
Phys. Chem. Chem. Phys., 2018, 20 (14), 9309-9320

[19] J. v. Vangerow, F. Coppens, A. Leal, et al.:
Imaging Excited-State Dynamics of Doped He Nanodroplets in Real-Time
J. Phys. Chem. Lett., 2017, 8 (1), 307-312

[18] A. Sieg, J. v. Vangerow, F. Stienkemeier, et al.:
Desorption Dynamics of Rb₂ Molecules Off the Surface of Helium Nanodroplets
J. Phys. Chem. A, 2016, 120 (39), 7641-7649

[17] J. v. Vangerow, A. S. Bogomolov, N. V. Dozmorov, et al.:
Role of ion-pair states in the predissociation dynamics of Rydberg states of molecular iodine
Phys. Chem. Chem. Phys., 2016, 18 (28), 18896-18904

[16] J. v. Vangerow, O. John, F. Stienkemeier, M. Mudrich:
Dynamics of solvation and desolvation of rubidium attached to He nanodroplets
J. Chem. Phys., 2015, 143 (3), 034302-1-03402-9

[15] H. Schmidt, J. v. Vangerow, F. Stienkemeier, et al.:
Predissociation dynamics of lithium iodide
J. Chem. Phys., 2015, 142 (4), 044303-1-044303-8

[14] J. Vangerow, A. Sieg, F. Stienkemeier, et al.:
Desorption Dynamcis of Heavy Alkali Metal Atoms (Rb, Cs) Off the Surface of Helium Nanodroplets
J. Phys. Chem. A, 2014, 118 (33), 6604-6614

[13] A. S. Bogomolov, B. Grüner, S. A. Kochubei, et al.:
Predissociation of high-lying Rydberg states of molecular iodine via ion-pair states
J. Chem. Phys., 2014, 140 (12), 124311-1-124311-9

[12] C. Giese, T. Mullins, B. Grüner, et al.:
Formation and relaxation of RbHe exciplexes on He nanodroplets studied by femtosecond pump and picosecond probe spectroscopy
J. Chem. Phys., 2012, 137 (24), 244307-1-244307-7

[11] L. Fechner, B. Grüner, A. Sieg, et al.:
Photoionization and imaging spectroscopy of rubidium atoms attached to helium nanodroplets
Phys. Chem. Chem. Phys., 2012, 14 (11), 3843-3851

[10] C. Giese, F. Stienkemeier, M. Mudrich, et al.:
Homo- and heteronuclear alkali metal trimers formed on helium nanodroplets. Part II. Femtosecond spectroscopy and spectra assignments
Phys. Chem. Chem. Phys., 2011, 13 (42), 18769-18780

[9] B. Grüner, M. Schlesinger, P. Heister, et al.:
Vibrational relaxation and dephasing of Rb2 attached to helium nanodroplets
Phys. Chem. Chem. Phys., 2011, 13 (15), 6816-6826

[8] M. Schlesinger, M. Mudrich, F. Stienkemeier, W. Strunz:
Dissipative vibrational wave packet dynamics of alkali dimers attached to helium nanodroplets
Chem. Phys. Lett., 2010, 490 (4-6), 245-248

[7] M. Mudrich, P. Heister, T. Hippler, et al.:
Spectroscopy of triplet states of Rb₂ by femtosecond pump-probe photoionization of doped helium nanodroplets
Phys. Rev. A, 2009, 80 (4), 042512-1-042512-12

[6] M. Mudrich, F. Stienkemeier, G. Droppelmann, et al.:
Quantum Interference Spectroscopy of Rubidium-Helium Exciplexes Formed on Helium Nanodroplets
Phys. Rev. Lett., 2008, 100 (2), 023401-1-023401-4

[5] P. Claas, G. Droppelmann, C. P. Schulz, M. Mudrich, F. Stienkemeier:
Wave Packet Dynamics in Triplet States of Na2 Attached to Helium Nanodroplets
J. Phys. Chem. A, 2007, 111 (31), 7537-7541

[4] P. Claas, G. Droppelmann, C. P. Schulz, M. Mudrich, F. Stienkemeier:
Wave packet dynamics of K₂ attached to helium nanodroplets
J. Phys. B: At. Mol. Opt. Phys., 2006, 39 (19), 1151-1168

[3] G. Droppelmann, O. Bünermann, C. P. Schulz, F. Stienkemeier:
Formation Times of RbHe Exciplexes on the Surface of Superfluid vs. Normalfluid Helium Nanodroplets
Phys. Rev. Lett., 2004, 93 (2), 023402-1-023402-4

[2] C. P. Schulz, P. Claas, F. Stienkemeier:
Formation of K*He Exciplexes on the Surface of Helium Nanodroplets Studied in Real Time
Phys. Rev. Lett., 2001, 87 (15), 153401-1-153401-4

[1] F. Stienkemeier, F. Meier, A. Hägele, et al.:
Coherence and Relaxation in Potassium-Doped Helium Droplets Studied by Femtosecond Pump-Probe Spectroscopy
Phys. Rev. Lett., 1999, 83 (12), 2320-2323

Kontakt:

Dr. Sebastian Hartweg

Prof. Dr. Frank Stienkemeier

Funding

Deutsche Forschungsgemeinschaft

European Research Council

RTG DynCAM

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