Description:

Title: Spectroscopy of Metal Containing Diatomic Molecules

Speaker: Prof. Timothy Steimle, Arizona State University

Abstract: 

Small metal containing molecules have become ideal venues for testing Fundamental Physics, producing ultra-cold samples, investigating relativistic effects, and probing the atmospheres of cool stars and exoplanets. These molecules have non-zero magnetic and electric dipole moments which facilitate kinetic energy manipulation. Furthermore, they serve as remote probes of static electric and magnetic fields via analyses of their optical Stark and Zeeman spectra. In the context of Fundamental Physics 1, YbF, ThO, HfF+, WC, and PbO are venues for electric dipole moment (EDM) investigations of the electron (eEDM), whereas TaN, YbF, ThO, ThF+, HfF+, HgF and BaF are proposed2 for magnetic quadrupole moment (MQM) induced EDM studies. In the context of ultra-cold molecule production, direct laser slowing and cooling has been demonstrated for SrF3, and is being attempted for CaF4. In the context of stellar and exoplanet atmospheres probes, TiO and VO are the molecules of choice5.
Understanding the high resolution electronic spectra of these simple molecules is essential for the success of past, and proposed experiments. Although “simple” from a chemists’ perspective, modelling the high density of interacting rotation/vibration/electronic states of metal containing molecules remains challenging. A central theme of diatomic molecular models is the construction and use of the effective Hamiltonian, and through it precise definitions of the molecular constants or parameters. The effective Hamiltonian is derived from a consideration of the fundamental true Hamiltonian, although the word ‘true’ must be used with caution. The nature/assumptions of diatomic effective Hamiltonians will be presented and high resolution electronic spectra of ThO, TaN, and VO will be used as examples.

References
1. B. M. Roberts, V. A. Dzuba and V. V. Flambaum, Annu. Rev. Nucl. Part. Sci. 65, 63 (2015).
2. V. V. Flambaum, D. DeMille and M. G. Kozlov, Phys. Rev. Lett. 113 (10), 103003/103001 (2014).
3. J. F. Barry, D. J. McCarron, E. B. Norrgard, M. H. Steinecker and D. DeMille, Nature (London, U. K.) 512 (7514), 286 (2014).
4. M. R. Tarbutt and T. C. Steimle, Phys. Rev. A: At., Mol., Opt. Phys. 92 (5-A), 053401/053401 (2015).
5. J.J. Fortney et al. Ap.J. 678, 1419 (2008).

Host: Brian Odom

Keywords: Physics, Astronomy, AMO