Quantifying the dynamical information content of pulsed, planar laser-induced fluorescence measurements.

Knight, Adam G, Olivares, Carlota Sieira, Roman, Maksymilian J ORCID: 0000-0002-5113-9470, Moon, Daniel R, Lane, Paul D, Costen, Matthew L and McKendrick, Kenneth G (2023) Quantifying the dynamical information content of pulsed, planar laser-induced fluorescence measurements. The Journal of chemical physics, 158 (24). p. 244705.

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Official URL: http://dx.doi.org/10.1063/5.0153321

Abstract

We have analyzed the effects of the spreads in experimental parameters on the reliability of speeds and angular distributions extracted from a generic surface-scattering experiment based on planar laser-induced fluorescence detection. The numerical model assumes a pulsed beam of projectile molecules is directed at a surface. The spatial distribution of the scattered products is detected by imaging the laser-induced fluorescence excited by a thin, pulsed sheet of laser light. Monte Carlo sampling is used to select from realistic distributions of the experimental parameters. The key parameter is found to be the molecular-beam diameter, expressed as a ratio to the measurement distance from the point of impact. Measured angular distributions are negligibly distorted when this ratio is <∼10%. Measured most-probable speeds are more tolerant, being undistorted when it is <∼20%. In contrast, the spread of speeds or of corresponding arrival times in the incident molecular beam has only very minor systematic effects. The thickness of the laser sheet is also unimportant within realistic practical limits. These conclusions are broadly applicable to experiments of this general type. In addition, we have analyzed the specific set of parameters designed to match the experiments on OH scattering from a liquid perfluoropolyether (PFPE) surface in the Paper I [Roman et al., J. Chem. Phys. 158, 244704 (2023)]. This reveals that the detailed form of the molecular-beam profile is important, particularly on apparent angular distributions, for geometric reasons that we explain. Empirical factors have been derived to correct for these effects.

Item Type:	Article
Divisions:	Faculty of Science and Engineering > School of Physical Sciences
Depositing User:	Symplectic Admin
Date Deposited:	01 Aug 2023 07:22
Last Modified:	14 Aug 2023 23:08
DOI:	10.1063/5.0153321
Open Access URL:	https://pubs.aip.org/aip/jcp/article/158/24/244705...
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3172006