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Rotationally Resolved Vacuum Ultraviolet Resonance-Enhanced Multiphoton Ionization (VUV REMPI) of Acetylene via the
Alice F Schmidt-May1,2, Monika Grütter1,2, Jannis Neugebohren1,2
1Institut für Physikalische Chemie, Georg-August-Universität Göttingen , Tammannstraße 6, 37077 Göttingen, Germany.
The Journal of Physical Chemistry. A
|April 14, 2016
Summary
We developed a new resonance-enhanced multiphoton ionization (REMPI) method for acetylene. This technique provides detailed insights into molecular excitation, including bending modes, and can be applied to other small molecules.
Area of Science:
- Molecular Spectroscopy
- Quantum Chemistry
- Atomic and Molecular Physics
Background:
- Acetylene spectroscopy is crucial for understanding molecular dynamics.
- Rydberg states play a key role in molecular photoionization processes.
- Previous methods lacked detailed rotational and bending mode resolution.
Purpose of the Study:
- To develop a novel 1+1' resonance-enhanced multiphoton ionization (REMPI) scheme for acetylene.
- To achieve partial rotational resolution and detect excitation in cis- and trans-bending modes.
- To explore the applicability of this REMPI scheme to other small molecules.
Main Methods:
- Utilized a 1+1' REMPI scheme.
- Employed vacuum ultraviolet (VUV) photons generated via resonant four-wave mixing (FWM) in krypton.
- Investigated acetylene (C2H2) and its deuterated isotopologue (C2D2).
Main Results:
- Observed nine distinct spectral bands in acetylene and C2D2 within the 79,200–80,500 cm⁻¹ range.
- Provided partial rotational resolution, enabling detailed analysis of spectral features.
- Identified and assigned excitation in both cis- and trans-bending modes.
Conclusions:
- The developed REMPI scheme offers enhanced spectral resolution for acetylene.
- The findings suggest alternative assignments for previously reported Renner-Teller split bands.
- This versatile REMPI approach is potentially applicable to other small molecules with picosecond lifetime Rydberg states.
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