2023/01/10 by Gergana D. Borisova, Borisova, Gergana D., Paula Barber Belda +21
Physics and Astronomy · #Laser-Matter Interactions and Applications #Advanced Chemical Physics Studies #Spectroscopy and Quantum Chemical Studies
paper · pdf · doi:10.1103/physrevresearch.6.033326
We observe and modify a molecular vibrational wave packet in an electronically excited state of the neutral hydrogen molecule. In an extreme-ultraviolet (XUV) time-domain absorption spectroscopy experiment, we launch a vibrational wave packet in the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mrow> <a:mi>D</a:mi> <a:mmultiscripts> <a:mi mathvariant="normal">Π</a:mi> <a:mi>u</a:mi> <a:none/> <a:mprescripts/> <a:none/> <a:mn>1</a:mn> </a:mmultiscripts> <a:mspace width="0.16em"/> <a:mn>3</a:mn> <a:mi mathvariant="normal">p</a:mi> <a:mi>π</a:mi> </a:mrow> </a:math> state of <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"> <e:msub> <e:mi mathvariant="normal">H</e:mi> <e:mn>2</e:mn> </e:msub> </e:math> and track its time evolution via the coherent dipole response. The reconstructed time-dependent dipole from experimentally measured XUV absorption spectra provides access to the revival of the vibrational wave packet, which we control via an intense near-infrared (NIR) pulse. Tuning the intensity of the NIR pulse, we observe the revival of the wave packet to be significantly modified, which is supported by the results of a multilevel simulation as well as an analytical model based on state-specific phase shifts. The NIR field is applied only 7 fs after the creation of the wave packet but influences its evolution up to at least its first revival at 270 fs. This experimental approach for nonlocal-in-time laser modification of quantum dynamics in a pump-control scheme enabled by molecular self-probing is generally applicable to a large range of molecules and materials as it only requires the observation of absorption spectra. Published by the American Physical Society 2024