Determining the Masses of Ions in a Paul Trap

Charged particles can be confined in three dimensional space by the combined static and time-dependent electric fields created in radiofrequency ("Paul") traps. Cooling can damp out an ion's motion, and oscillating electric fields can drive it resonantly to higher amplitudes. Using the LAMMPS and (py)LIon simulation packages, we investigate the effects of driving ions over a range of frequencies. Our results show resonant behavior that aligns with the theoretical frequencies, both when simulating with the pseudopotential approximation and with the true time-varying electric potential of the trap. By studying the behavior of increasingly complex multi-particle and multi-species ions, we aim to find an efficient experimental sequence for determining the number and charge-to-mass ratio of the trapped ions.