Interplay between ultrafast electronic and librational dynamics in liquid nitrobenzene probed with two-color four-wave mixing

Fuente: arXiv
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Auteurs principaux: Shivaram, Niranjan, Thurston, Richard, Belkacem, Ali, Weber, Thorsten, Tan, Liang Z., Slaughter, Daniel S.
Format: Preprint
Publié: 2025
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author Shivaram, Niranjan
Thurston, Richard
Belkacem, Ali
Weber, Thorsten
Tan, Liang Z.
Slaughter, Daniel S.
author_facet Shivaram, Niranjan
Thurston, Richard
Belkacem, Ali
Weber, Thorsten
Tan, Liang Z.
Slaughter, Daniel S.
contents We present an experimental and theoretical study of the interplay between ultrafast electron dynamics and librational dynamics in liquid nitrobenzene. A femtosecond ultraviolet pulse and two femtosecond near infrared pulses interact with nitrobenzene molecules, generating a four-wave mixing nonlinear signal that is measured in the Optical Kerr Effect geometry. The near infrared nonlinear signal is measured to be non-zero only at negative time delays, corresponding to the near infrared pulses arriving earlier than the ultraviolet pulse. We perform time-dependent Quantum Master Equation calculations, which include a classical libration model, to simulate the experiment. The simulations support the conclusion that the near infrared pulses launch librational motion, while simultaneously creating electronic coherences that result in a libration-modulated electronic nonlinear response. Furthermore, we conclude that the measured nonlinear optical signal corresponds to a non-parametric process that leaves the molecules in an excited electronic state. This work provides new insight into ultrafast nonlinear optical interactions in liquids and is an important step towards probing ultrafast electronic coherences in large molecules in the liquid phase.
format Preprint
id arxiv_https___arxiv_org_abs_2506_04160
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Interplay between ultrafast electronic and librational dynamics in liquid nitrobenzene probed with two-color four-wave mixing
Shivaram, Niranjan
Thurston, Richard
Belkacem, Ali
Weber, Thorsten
Tan, Liang Z.
Slaughter, Daniel S.
Chemical Physics
Optics
We present an experimental and theoretical study of the interplay between ultrafast electron dynamics and librational dynamics in liquid nitrobenzene. A femtosecond ultraviolet pulse and two femtosecond near infrared pulses interact with nitrobenzene molecules, generating a four-wave mixing nonlinear signal that is measured in the Optical Kerr Effect geometry. The near infrared nonlinear signal is measured to be non-zero only at negative time delays, corresponding to the near infrared pulses arriving earlier than the ultraviolet pulse. We perform time-dependent Quantum Master Equation calculations, which include a classical libration model, to simulate the experiment. The simulations support the conclusion that the near infrared pulses launch librational motion, while simultaneously creating electronic coherences that result in a libration-modulated electronic nonlinear response. Furthermore, we conclude that the measured nonlinear optical signal corresponds to a non-parametric process that leaves the molecules in an excited electronic state. This work provides new insight into ultrafast nonlinear optical interactions in liquids and is an important step towards probing ultrafast electronic coherences in large molecules in the liquid phase.
title Interplay between ultrafast electronic and librational dynamics in liquid nitrobenzene probed with two-color four-wave mixing
topic Chemical Physics
Optics
url https://arxiv.org/abs/2506.04160