Impulsive laser-induced alignment of OCS molecules at FERMI

• Published in: Physical chemistry chemical physics : PCCP 2017-08, Vol.19 (3), p.19733-19739
• Main Authors: Di Fraia, Michele, Finetti, Paola, Richter, Robert, Prince, Kevin C, Wiese, Joss, Devetta, Michele, Negro, Matteo, Vozzi, Caterina, Ciriolo, Anna G, Pusala, Aditya, Demidovich, Alexander, Danailov, Miltcho B, Karamatskos, Evangelos T, Trippel, Sebastian, Küpper, Jochen, Callegari, Carlo
• Format: Article
• Language: English
• ISSN: 1463-9076; 1463-9084
• DOI: 10.1039/c7cp01812f

We demonstrate the experimental realization of impulsive alignment of carbonyl sulfide (OCS) molecules at the Low Density Matter Beamline (LDM) at the free-electron laser FERMI. OCS molecules in a molecular beam were impulsively aligned using 200 fs pulses from a near-infrared laser. The alignment was probed through time-delayed ionization above the sulphur 2p edge, resulting in multiple ionization via Auger decay and subsequent Coulomb explosion of the molecules. The ionic fragments were collected using a time-of-flight mass spectrometer and the analysis of ion-ion covariance maps confirmed the correlation between fragments after Coulomb explosion. The analysis of the CO + and S + channels allowed us to extract the rotational dynamics, which is in agreement with our theoretical description as well as with previous experiments. This result opens the way for a new class of experiments at LDM within the field of coherent control of molecules with the possibilities that a precisely synchronized optical-pump XUV-probe laser setup like FERMI can offer. OCS full rotational revival dynamics induced by impulsive NIR alignment monitored by Coulomb explosion correlated fragments after S 2p excitation.