A new action photoelectron spectroscopy for anions

Area of Science:

• Physical Chemistry
• Spectroscopy
• Atomic and Molecular Physics

Background:

• Anion photodetachment spectroscopy provides crucial insights into the electronic structure of negative ions.
• Existing methods like zero electron kinetic energy (ZEKE) spectroscopy have limitations that can affect spectral resolution and interpretation.
• There is a need for advanced spectroscopic techniques to overcome these challenges and enhance the study of molecular anions.

Purpose of the Study:

• To introduce a novel experimental approach for anion photodetachment spectroscopy.
• To overcome the limitations associated with the zero electron kinetic energy method.
• To achieve high-resolution spectroscopic data for molecular anions.

Main Methods:

• Utilized a modified magnetic bottle photoelectron spectrometer (MBPES) for anion photodetachment.
• Employed a tunable laser to detach electrons from mass-selected anions.
• Implemented a low voltage pulse to counteract Doppler broadening and recorded spectra based on time-of-flight windows corresponding to fixed electron kinetic energy, termed photoelectron action spectroscopy at constant kinetic energy (PEACE).

Main Results:

• Achieved a best spectral resolution of 0.65 meV for electrons with 1.5 meV kinetic energy.
• Presented a PEACE spectrum of the HgCl(-) anion.
• Demonstrated that the PEACE method offers comparable resolution and data acquisition rates to the slow electron velocity map imaging technique.

Conclusions:

• The developed PEACE method is a powerful new tool for high-resolution anion photodetachment spectroscopy.
• PEACE circumvents key limitations of the ZEKE method, enabling more precise studies of molecular anions.
• This technique holds significant potential for advancing the understanding of electronic structures and dynamics in negative ions.