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Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Electronic spectroscopy of the HCCN radical
Masakazu Nakajima1, Hitomi Toyoshima, Shigenori Sato
1Department of Basic Science, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan.
The Journal of Chemical Physics
|May 3, 2013
Summary
The electronic transition of HCCN/DCCN radicals was studied using laser-induced fluorescence spectroscopy. Anomalous rotational line intensities suggest a level-dependent non-radiative decay in the excited state.
Area of Science:
- Physical Chemistry
- Spectroscopy
- Quantum Chemistry
Background:
- The HCCN and DCCN radicals are transient species relevant to combustion and astrochemistry.
- Understanding their electronic structure and dynamics is crucial for modeling chemical processes.
Purpose of the Study:
- To investigate the Ã(3)A"–X̃(3)Σ(-) electronic transition of HCCN and DCCN radicals.
- To characterize the excited state molecular constants and ground state vibrational structure.
- To explore non-radiative decay pathways in the excited electronic state.
Main Methods:
- Laser-induced fluorescence (LIF) spectroscopy was employed to observe rotationally resolved excitation spectra.
- Fluorescence depletion spectroscopy was used to probe non-fluorescent vibronic levels.
- Dispersed fluorescence (DF) spectroscopy was utilized to determine the ground electronic state vibrational structure.
Main Results:
- Effective molecular constants for the upper electronic state of HCCN and DCCN were determined from LIF spectra.
- Anomalous rotational line intensities indicated a level-dependent non-radiative decay process.
- Vibrational structures in the ground state were assigned using ab initio calculations and fluorescence depletion/dispersed fluorescence spectra.
Conclusions:
- The study provides detailed spectroscopic characterization of the Ã(3)A"–X̃(3)Σ(-) transition in HCCN/DCCN.
- Evidence for non-radiative decay dynamics in the excited state was obtained.
- Ab initio calculations aided in the assignment of vibrational modes in the ground electronic state.
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