Note: A simple method to suppress the artificial noise for velocity map imaging spectroscopy

Area of Science:

• Spectroscopy
• Atomic and Molecular Physics
• Chemical Physics

Background:

• Velocity-map imaging spectroscopy is crucial for analyzing molecular dynamics.
• Reconstructed 3D images often suffer from artificial noise, particularly along the central line.
• This noise can obscure subtle structures and vibrational information.

Purpose of the Study:

• To introduce a simple and effective method for suppressing central line noise in 3D reconstructed images.
• To enhance the resolution of weak structures and vibrational excitations in spectroscopic experiments.
• To improve the accuracy of data analysis in velocity-map imaging spectroscopy.

Main Methods:

• A pre-processing step using an angular tailored method is applied to raw 2D projection data.
• The method specifically targets and reduces signal counts near the central z-axis.
• The technique was tested on photoelectron velocity-map imaging of O(-) and Au(-)⋅NH3.

Main Results:

• The proposed pre-processing method significantly reduces central line noise in reconstructed 3D images.
• Demonstrated effectiveness in velocity-map imaging experiments involving O(-) and Au(-)⋅NH3.
• The noise suppression allows for better visualization of weak structures and vibrational states.

Conclusions:

• The angular tailored pre-processing method is a simple yet powerful tool for noise reduction in velocity-map imaging.
• This technique enhances the ability to study subtle phenomena like vibrational excitation near the photon threshold.
• The method offers significant advantages for detailed analysis in photodetachment, photoionization, and photodissociation studies.