Related Experiment Videos
Simultaneous ejection of two molecular ions from keV gold atomic and polyatomic projectile impacts
R D Rickman1, S V Verkhoturov, E S Parilis
1Department of Chemistry, Texas A&M University, College Station, TX 77842-3012, USA.
Physical Review Letters
|March 6, 2004
Summary
We measured the simultaneous ejection of phenylalanine (Ph) ions using gold cluster impacts. Ion yields increased significantly with projectile energy, indicating distinct emission pathways for atomic versus polyatomic projectiles.
Area of Science:
- * Surface science and analytical chemistry.
- * Atomic and molecular physics.
- * Materials science.
Background:
- * Understanding molecular ion emission from materials under ion bombardment is crucial for surface analysis and modification.
- * Previous studies have primarily focused on atomic projectiles, leaving the effects of polyatomic projectiles less explored.
- * Phenylalanine (Ph) is a biologically relevant amino acid often used as a model system in such experiments.
Purpose of the Study:
- * To experimentally investigate the simultaneous ejection of two molecular ions from phenylalanine (Ph) targets.
- * To determine the influence of projectile energy and complexity (atomic vs. cluster) on ion emission yields.
- * To analyze the coemission of Ph ions and Ph dimer to elucidate emission mechanisms.
Main Methods:
- * Bombardment of phenylalanine targets with gold cluster ions (Au(+)(n), 1 <= n <= 4) at energies from 17 to 56 keV.
- * Measurement of ion yields for single Ph emission, coemission of two Ph ions, and Ph dimer emission.
- * Calculation of correlation coefficients for the coemission of two Ph ions.
Main Results:
- * The first experimental data on simultaneous ejection of two molecular ions from phenylalanine under gold cluster impact are presented.
- * Coemitted ion yields showed substantial increases (1-2 orders of magnitude) with increasing projectile energy and cluster size.
- * Correlation coefficients indicated different emission pathways when comparing atomic and polyatomic projectile impacts.
Conclusions:
- * Polyatomic projectiles, specifically gold clusters, significantly enhance the simultaneous ejection of molecular ions from phenylalanine.
- * The observed increase in yields suggests energy and momentum transfer mechanisms are highly dependent on projectile complexity.
- * The analysis of coemission behavior provides insights into the distinct emission dynamics governed by atomic versus polyatomic ion bombardment.