Study of Interatomic Potentials in ZnS-Crystal-GRID Experiments Versus Ab Initio Calculations.

Area of Science:

• Nuclear physics
• Solid-state physics

Background:

• Understanding nuclear level lifetimes is crucial for nuclear structure models.
• Previous studies on Sulfur-33 (³³S) have reported a specific lifetime for the 3221 keV excitation level.

Purpose of the Study:

• To perform Crystal-GRID measurements on ZnS single crystals.
• To investigate the line shape of nuclear resonance scattering.
• To re-evaluate the lifetime of the 3221 keV level in ³³S.

Main Methods:

• Utilized Crystal-GRID (Crystal-Growth-Resonance-Induced-De-excitation) spectroscopy.
• Employed ZnS single crystals as the target material.
• Analyzed the observed line shape for asymmetries and structure.

Main Results:

• Observed an unprecedented asymmetric Crystal-GRID line shape for the first time.
• Preliminary analysis indicates the previously reported lifetime for the 3221 keV level in ³³S is likely too short.
• Determined a preliminary lifetime of approximately 60 femtoseconds (fs) for this level.

Conclusions:

• The observed asymmetric line shape is attributed to a longer lifetime of the 3221 keV level in ³³S than previously assumed.
• The measured lifetime of ~60 fs results in a less structured line shape compared to theoretical calculations based on shorter lifetimes.
• This finding necessitates a revision of nuclear structure models concerning the 3221 keV level in ³³S.