ROTATIONALLY-RESOLVED SCATTERING OF FORMALDEHYDE FROM THE Au(111) SURFACE: AN AXIS SPECIFIC ROTATIONAL RAINBOW AND ITS ROLE IN TRAPPING PROBABILITY

Park, Barratt

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https://hdl.handle.net/2142/96889 Copy

Description

Title

ROTATIONALLY-RESOLVED SCATTERING OF FORMALDEHYDE FROM THE Au(111) SURFACE: AN AXIS SPECIFIC ROTATIONAL RAINBOW AND ITS ROLE IN TRAPPING PROBABILITY

Author(s)

Park, Barratt

Contributor(s)

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

Issue Date

6/21/2017

Keyword(s)

Dynamics and kinetics

Abstract

The conversion of translational to rotational motion often plays a major role in the trapping of small molecules at surfaces, a crucial first step for a wide variety of chemical processes that occur at gas-surface interfaces. However, to date most quantum-state resolved surface scattering experiments have been performed on diatomic molecules, and very little detailed information is available about how the structure of non-linear polyatomic molecules influences the mechanisms for energy exchange with surfaces. In the current work, we employ a new rotationally-resolved $1+1'$ resonance-enhanced multiphoton ionization (REMPI) scheme to measure rotational distribution in formaldehyde molecules directly scattered from the Au(111) surface at incident kinetic energies in the range 0.3--1.2 eV. The results indicate a pronounced propensity to excite $a$-axis rotation (twirling) rather than $b$- or $c$-axis rotation (tumbling or cartwheeling), and are consistent with a rotational rainbow scattering model. Classical trajectory calculations suggest that the effect arises---to zeroth order---from the three-dimensional shape of the molecule (steric effects). The results have broad implications for the enhanced trapping probability of prolate and near-prolate molecules at surfaces.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/96889

DOI

10.15278/isms.2017.WH07

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