University of Illinois Urbana-Champaign

Imaging of rotational wave packets in molecules and clusters

Ohshima, Yasuhiro

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https://hdl.handle.net/2142/107326

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Title
Imaging of rotational wave packets in molecules and clusters
Author(s)
Ohshima, Yasuhiro
Issue Date
2020-06-22
Keyword(s)
Plenary
Date of Ingest
2020-06-26T03:04:07Z
Abstract
Irradiation of ultrashort laser pulses onto a molecular ensemble inherently results in the creation of a quantum wave packet (WP), i.e., a coherent superposition of several (or sometimes many) eigenstates. It is an ultimate goal in modern molecular physics to establish the way for creating WPs as designed, and it is also essential for advanced WP manipulation to know how to characterize the WP experimentally. Over the last two decades, intense nonresonant excitation has been extensively adopted to realize “nonadiabatic molecular alignment” or “nonadiabatic rotational excitation,” where the impulsive torque due to anisotropic molecular polarizability instantaneously align the molecules and their rotation is coherently excited in the vibronic ground-state manifold.\footnote{Y. Ohshima and Hasegawa, Int. Rev. Chem. Phys. \textbf{29}, 619 (2010).} Evolution of the rotational WP thus created can be tracked as a series of images for the time-dependent molecular orientational distribution, e.g., by implementing pump-probe Coulomb explosion ion-imaging measurements. We will represent some examples of such “molecular movies” taken with a newly configured imaging configuration,\footnote{K. Mizuse, R. Fujimoto, and Y. Ohshima, Rev. Sci. Instrum. \textbf{90}, 103107 (2019).} which is capable to clearly capture the time-dependent nodal structures, instantaneous alignment, angular dispersion, and fractional revivals of the rotational WP while the molecular ensemble keeps rotating in one direction.\footnote{K. Mizuse, K. Kitano, H. Hasegawa, and Y. Ohshima, Sci. Adv. \textbf{1}, e1400185 (2015).} Wave-packet imaging will also be developed as a new approach in molecular spectroscopy, since energy intervals between the eigenstates that constitute the WP are encoded in the molecular movies shoot by the method. We will show some recent results along this direction; rotational spectra have been successfully extracted for homodimers of nonpolar molecules, which have been scarcely investigated because of the difficulty in recording or analyzing their IR or microwave spectrum.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
Text
Genre of Resource
Conference Paper / Presentation
Language
eng
Permalink
http://hdl.handle.net/2142/107326
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Copyright 2020 is held by the Author(s)

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Abstracts & Presentations - 2020 International Symposium on Molecular Spectroscopy PRIMARY