Time-Resolved Dissociation Dynamics of Iodomethane Resulting from Rydberg and Valence Excitation

Arne Baumann; Dimitrios Rompotis; Oliver Schepp; Marek Wieland; Markus Drescher

doi:10.1021/acs.jpca.8b01248

Time-Resolved Dissociation Dynamics of Iodomethane Resulting from Rydberg and Valence Excitation

J Phys Chem A. 2018 May 31;122(21):4779-4784. doi: 10.1021/acs.jpca.8b01248. Epub 2018 May 18.

Authors

Arne Baumann^{1

2}, Dimitrios Rompotis³, Oliver Schepp¹, Marek Wieland^{1

2

4}, Markus Drescher^{1

2

4}

Affiliations

¹ Institute for Experimental Physics , University Hamburg , Hamburg 22761 , Germany.
² The Hamburg Centre for Ultrafast Imaging-CUI , Hamburg 22761 , Germany.
³ Deutsches Elektronen-Synchrotron-DESY , Hamburg 22607 , Germany.
⁴ Center for Free-Electron Laser Science-CFEL , Hamburg 22607 , Germany.

PMID: 29746126
DOI: 10.1021/acs.jpca.8b01248

Abstract

Rydberg excitations in the vacuum ultraviolet spectral range may open up molecular photoreaction pathways not accessible from lower-lying valence states. Here, single-shot UV/VUV pump-probe spectroscopy was used to study the photodissociation dynamics of iodomethane after 268 nm excitation in the A-band and excitation of the 6p (² E_3/2) Rydberg state at 161 nm. By combining weak-field VUV single-photon ionization with sub-10 fs temporal resolution and the superior statistical accuracy of the single-shot technique, sub-30 fs wave packet dynamics upon excitation in the A-band by a UV pump pulse were disclosed. Population transfer from the Rydberg state to the 2 ¹ A₁ valence state leading to 100 fs dissociation dynamics was observed by utilizing the same methodology in a VUV-pump/UV-probe scheme.