%0 Journal Article %T Characterisation and modeling of a pulsed molecular beam %+ Dynamique Réactionnelle (DyR) %+ LUmière et MOlécules (LUMO) %A Lietard, A. %A Gallician, G. %A Tan, J. %A Gaveau, M.-A. %A Briant, M. %A Soep, B. %A Mestdagh, J.-M. %A Poisson, L. %< avec comité de lecture %@ 0026-8976 %J Molecular Physics %I Taylor & Francis %V 119 %P e1737743 %8 2021 %D 2021 %R 10.1080/00268976.2020.1737743 %Z Chemical Sciences/Theoretical and/or physical chemistry %Z Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph]Journal articles %X 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. %G English %2 https://cea.hal.science/cea-03053669/document %2 https://cea.hal.science/cea-03053669/file/Article_pulsed_valve_v3b.pdf %L cea-03053669 %U https://cea.hal.science/cea-03053669 %~ CEA %~ CNRS %~ IRAMIS-LIDYL %~ CEA-UPSAY %~ UNIV-PARIS-SACLAY %~ TEST-HALCNRS %~ UNIVERSITE-PARIS-SACLAY %~ ANR %~ GS-ENGINEERING %~ IRAMIS %~ GS-CHIMIE %~ GS-PHYSIQUE %~ INSTITUT-SCIENCES-LUMIERE