Analysis of the Impacts of Reactant Molecular Beam Velocity Spreads on Product Velocity Resolution in Crossed Beam Experiments
Owing to its convenience and accura-cy in providing detailed information about quantum state populations and angular distributions of reaction prod-ucts,the velocity map imaging tech-nique has been extensively employed in crossed beam experiments for prod-uct detection.In crossed beam experi-ments,the two reactant beams al-ways exhibit certain spreads in both magnitude and direction of the velocity,which will blur the scattered product images and lower the resolution of product detection.To systematically investigate the influence of reac-tant velocity spreads on the resolution of product detection in crossed beam experiments,a general model based on velocity vector analysis is constructed and presented here.The im-pacts of spreads of the magnitude and direction of the reactant velocities on the image resolu-tion under three typical experimental conditions are analyzed,and ways for improving the resolution are briefly discussed.Guided by the above analysis,a fine adjustment of the Ar+ion beam was performed,and the product image resolution for the charge transfer reaction Ar+(2P3/2)+N2 is effectively improved,particularly in the backward scattering region,which provides more accurate information on the reaction dynamics.
Crossed molecular beamMolecular beamVelocity-map imagingMonte Carlo simulationProduct velocity resolution
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