A NEW ION DETECTION SCHEME FOR ION SPECTROSCOPY EQUIVALENT TO ZERO KINETIC-ENERGY PHOTOELECTRON-SPECTROSCOPY

A new scheme for the detection of ions produced by delayed pulsed field ionization of long-lived high-n Rydberg states (ZEKE Rydberg states) is presented. The equivalence of this new ion detection scheme with high resolution zero kinetic energy photoelectron (ZEKE) spectroscopy is proven by the simultaneous measurement of electrons and ions originating from the same ZEKE Rydberg states, taking into account the effects of pulsed and static low electric fields on the ZEKE Rydberg states. Using this ion detection, a rotationally resolved mass analyzed threshold ionization (MATI) spectrum of benzene with the same resolution (the rotational structure of the benzene cation) as the simultaneously recorded ZEKE photoelectron spectrum has been obtained.