Details

Autor(en) / Beteiligte

• Dole, Malcolm
• Mack, L. L.
• Hines, R. L.
• Mobley, R. C.
• Ferguson, L. D.
• Alice, M. B.

Titel

Molecular Beams of Macroions

Ist Teil von

• The Journal of chemical physics, 1968-09, Vol.49 (5), p.2240-2249

Erscheinungsjahr

1968

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• By means of electrospraying a dilute polymer solution into an evaporation chamber, negative macroions can be produced and a molecular beam formed by sampling the gaseous mixture of macroions, solvent, and nitrogen molecules with a nozzle-skimmer system of the Kantrowitz–Gray type. The macroion current can be detected by a Faraday cage after the light ions have been repelled from the beam by negative voltages on a repeller grid. Theoretical repeller voltages which best agree with the observed are those calculated by assuming a macroion velocity within 2% of the estimated supersonic beam velocity of 743 m sec−1. Polystyrene macroions of 51 000 weight-average amu tend to form dimers and trimers in the beam while larger polystyrene macroions of 411 000 weight-average amu appear mostly to be multiply charged single species. The results demonstrate that definite mass/charge states can be formed by the electrospray technique, that a considerable monochromatization of macroion velocities in the beam takes place, and that the macroions become highly concentrated relative to low-molecular-weight solvent and nitrogen ions during the transit time in the supersonic beam.