My research lies at the intersection of atomic and molecular physics investigating the varied mechanisms by which atoms bind to form molecules. As with almost all experimental studies in atoms and molecules the main challenge is precise control of light. Lasers can be used for trapping, cooling, exciting, ionizing, associating and dissociating atoms and molecules.

The present study is focused on lithium with current efforts mainly directed towards the contruction of a magneto-optical trap (MOT). Once this trap is built and optimized we will have a reliable system for trapping populations of lithium atoms cooled to 1 mK or less.

Figure 1 shows the playground in which this research will take place, relating the energy of pairs of isolated atoms to the potential energy curves of the ground state diatomic molecule and molecular ion. Note that each atom pair listed consists of one ground and one excited state atom; because the time between collisions in a MOT is much greater than the excited state lifetime, collisions between two excited atoms rarely take place.^[1]

Figure 1: Comparison of the energy levels of a pair of isolated lithium atoms[2] with the ground state potential energy curves of the lithium dimer[3] and its first ionic state.[4] Vibrational levels of the molecular ionic ground state are shown as well as the energy of the Li+-Li- ion pair. Note that the horizontal positions of the atomic levels bear no relation to the internuclear distance axis.

The long-term goals of the group involve the study of bound ion-pair states commonly known as heavy Rydberg systems.^[5] Consisting of a positive and a negative ion bound by the Coulomb force, these systems are in many ways similar to the well understood hydrogen atom with the anion playing the role of the electron. The large reduced mass of the system ensures that dynamic phenomena such as wavepackets occur on long timescales, presenting opportunities for excellent temporal resolution in experiments.

References
^[1] J J Blangé et al., J. Phys. B: At. Mol. Opt. Phys. 30 2789 (1997) ⇒
^[2] C. E. Moore, US Department of Commerce Circular 467
^[3] D.D. Konowalow and J.L. Fish, Chem. Phys. 84 463 (1984) ⇒
^[4] D.D. Konowalow and J.L. Fish, Chem. Phys. Lett. 104 210 (1984) ⇒
^[5] E. Reinhold and W. Ubachs, Molecular Physics 103 1329 (2005) ⇒

Top of Page