A 45-degree ion-extraction photoelectron velocity map imaging apparatus coupled to the DUV-IR mass spectrometry and spectroscopy instrument

Abstract

A photoelectron velocity-map imaging (VMI) apparatus has been developed from the DUV-IR photoionization mass spectrometry and spectroscopy instrument. A 45-degree plate-set is designed and combined with the upright reflection time-of-flight mass spectrometer (Re-TOFMS) to pick up target cluster anions and change their trajectory after the vertical reflection. Following the ion-extraction zone, the mass-selected cluster anions then pass through up-down and left-right trajectory adjustment and beam focus until the arrival at the photoelectron detachment zone to encounter the normal incidence of a pulsed UV laser. The detached electrons are subject to acceleration and detected by a dual micro-channel plate detector and imaging on the phosphor screen. This 45-degree ion-extraction photoelectron VMI setup not only expands the function of our DUV-IR instrument for structural chemistry but also facilitates the compatibility with the conventional upright reflection of TOFMS.