A 1+1′ RESONANCE-ENHANCED MULTIPHOTON IONIZATION SCHEME FOR ROTATIONALLY STATE-SELECTIVE DETECTION OF FORMALDEHYDE VIA THE A 1A2←X 1A1 TRANSITION

Park, Barratt

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https://hdl.handle.net/2142/96878 Copy

Description

Title

A 1+1′ RESONANCE-ENHANCED MULTIPHOTON IONIZATION SCHEME FOR ROTATIONALLY STATE-SELECTIVE DETECTION OF FORMALDEHYDE VIA THE A 1A2←X 1A1 TRANSITION

Author(s)

Park, Barratt

Contributor(s)

• Schaefer, Tim
• Wodtke, Alec
• Meyer, Sven
• Krueger, Bastian C.

Issue Date

6/20/2017

Keyword(s)

Small molecules

Abstract

The formaldehyde molecule is an important model system for understanding dynamical processes in small polyatomic molecules. However, prior to this work, there have been no reports of a resonance-enhanced multiphoton ionization (REMPI) detection scheme for formaldehyde suitable for rovibrationally state-selective detection in molecular beam scattering experiments. Previously reported tunable REMPI schemes are either non-rotationally resolved, involve multiple resonant steps, or involve many-photon ionization steps. In the current work, we present a new $1+1'$ REMPI scheme for formaldehyde. The first photon is tunable and provides rotational resolution via the vibronically allowed $mathrm{tilde{A}}$,$^1mathrm{A}_2leftarrowmathrm{tilde{X}}$,$^1mathrm{A}_1$ transition. Molecules are then directly ionized from the $mathrm{tilde{A}}$ state by one photon of 157~nm. The results indicate that the ionization cross section from the $4^1$ vibrational level of the $mathrm{tilde{A}}$ state is independent of the rotational level used as intermediate, to within experimental uncertainty. The $1+1'$ REMPI intensities are therefore directly proportional to the $mathrm{tilde{A}}leftarrowmathrm{tilde{X}}$ absorption intensities and can be used for quantitative measurement of $mathrm{tilde{X}}$-state population distributions. _x000d_

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/96878

DOI

10.15278/isms.2017.TK03

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