ZEKE spectroscopy basis

There is also the question of which zero-order basis is more natural for the experiment. Of course, here, too, simplicity is in the eye of the beholder, but as I already argued, to my mind, ZEKE spectroscopy points out the advantage of the inverse Bom-Oppenheimer zero-order basis. 

An extension of ZEKE spectroscopy is mass-analysed threshold ionization (MATI), photoelectron spectroscopy without photoelectrons . This is effectively the same experiment for every ZEKE electron produced, there must be a cation, and in MATI detection a signal is recorded from these ions. It is much harder to separate the ions produced from pulsed-field ionization of the ZEKE Rydberg states from the ever-present directly produced ions. Ions are much heavier than electrons and hence move more slowly, so a higher-voltage extraction pulse is required for the separation and the subsequent extraction and selection of the cations. The obvious advantage of this combination of ZEKE with mass spectrometry is the ability to select the cations on the basis of their mass. 

The factor limiting the resolution in ultraviolet photoelectron spectra is the inability to measure the kinetic energy of the photoelectrons with sufficient accuracy. The source of the problem points to a possible solution. If the photoelectrons could be produced with zero kinetic energy this cause of the loss of resolution would be largely removed. This is the basis of zero kinetic energy photoelectron (ZEKE-PE) spectroscopy. 

The improved numerical stability of the new deMon2K version also opened the possibility for accurate harmonic Franck-Condon factor calculations. Based on the combination of such calculations with experimental data from pulsed-field ionization zero-electron-kinetic energy (PFl-ZEKE) photoelectron spectroscopy, the ground state stmcture of V3 could be determined [272]. Very recently, this work has been extended to the simulation of vibrationaUy resolved negative ion photoelectron spectra [273]. In both works the use of newly developed basis sets for gradient corrected functionals was the key to success for the ground state stmcture determination. These basis sets have now been developed for aU 3d transition metal elements. With the simulation of vibrationaUy resolved photoelectron spectra of small transition metal clusters reliable stmcture and... 

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