NONLINEAR TIME-DOMAIN CRYOGENIC ION VIBRATIONAL SPECTROSCOPY WITH ULTRAFAST INFRARED PULSES

Ma, Zifan

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https://hdl.handle.net/2142/122444 Copy

Description

Title

NONLINEAR TIME-DOMAIN CRYOGENIC ION VIBRATIONAL SPECTROSCOPY WITH ULTRAFAST INFRARED PULSES

Author(s)

Ma, Zifan

Contributor(s)

• Fournier, Joseph
• Chen, Liangyi

Issue Date

2023-06-20

Keyword(s)

Mini-symposium: Spectroscopy with Cryogenic Ion Traps

Abstract

Nonlinear infrared spectroscopy in condensed phases provides valuable structural and dynamical information, yet interpreting the results can be challenging due to factors such as spectral congestion, solvent background, and low sensitivity. Cryogenic Ion Vibrational Spectroscopy (CIVS) offers a solution by measuring infrared spectra of isolated ions quenched into their lowest-energy configurations. Spectra are typically recorded indirectly using an action response, such as the photodissociation of weakly bound "tag" molecules like N₂. Traditionally, CIVS employs tunable single-color laser sources with a few cm⁻¹ bandwidth and ns pulse durations. However, the combination of ultrafast laser sources with the sensitivity of CIVS presents an exciting new platform for directly probing vibrational dynamics in complex molecular ion systems. In this context, the instrumentation and methodology for time-resolved CIVS will be discussed, alongside preliminary nonlinear (pump-probe) spectra of N₂-tagged tris(acetonitrile)tricarbonyl rhenium(I) (Re(CO)₃(CH₃CN)₃⁺·N₂) will be presented. The pump-probe experiments capture the bleaching signals of the asymmetric and symmetric carbonyl stretching modes. Excited-state absorption features are not observed, consistent with expected Feynman pathways and previous action-based nonlinear measurements. Interestingly, the intensities of the two carbonyl stretch transitions oscillate with pump-probe delay time, demonstrating coherent coupling between the modes. These studies showcase the potential of combining CIVS with ultrafast sources into a single platform, with expected extensions to two-dimensional nonlinear spectroscopy and other systems of chemical and biological interest.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

Handle URL

https://hdl.handle.net/2142/122444

DOI

https://doi.org/10.15278/isms.2023.6748

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