Characterisation and modeling of a pulsed molecular beam. (17th January 2021)

• Record Type: Journal Article
• Authors: Lietard, A.; Gallician, G.; Tan, J.; Gaveau, M.-A.; Briant, M.; Soep, B.; Mestdagh, J.-M.; Poisson, L.
• Is Part Of: Molecular physics. Volume 119:Number 1/2(2021)
• Publication Date: 2021-01-17
• Subjects: Molecular beams -- transition flow -- velocity map imaging -- pulsed valve -- chock wave; Molecules -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Molécules -- Périodiques; Chimie physique et théorique -- Périodiques; 539.6.05
• DOI: 10.1080/00268976.2020.1737743
• Languages: English
• ISSNs: 0026-8976

Abstract

Abstract : Standard techniques used in real-time reaction dynamics experiments, namely photoionization by a pulsed laser and velocity imaging are applied to document the time dependent velocity distribution of 2-hydroxypyridine (2-HP) molecules in a pulsed beam where 2-HP is seeded in either helium or argon. The purpose is to identify features which cannot be assigned to a pure free molecular (effusive in the present case) or a pure continuum (supersonic here) flow regime. The beam is generated in a two stage expansion, where the first stage is driven by a pulsed valve. The experimental work is complemented by simulations. Two phenomena retain the attention: (i) a slow return to the effusive flow regime after the valve opening has generated an intense supersonic flow; (ii) development of a shock wave a short time after the valve opening. GRAPHICAL ABSTRACT: