Thursday, Feb 8th: Zero-field nuclear magnetic resonance for direct detection of molecular chirality and parity nonconservation

Event Date: 

Thursday, February 8, 2018 - 3:45pm

Event Date Details: 

Refreshments served at 3:30pm.

Event Location: 

  • Elings Hall 1605
  • ABC...z Seminar Series

Molecular chirality is an extremely important yet often difficult to measure property.

Spectroscopicmethods to determine absolute chirality with high sensitivity and chemical specificityare highly sought after. In this talk I will show how molecular chiralitydirectly impacts the nuclear spin Hamiltonian through the geometry of theindirect nuclear spin-spin coupling (J-coupling) in electrically orientedmolecules. I then show how a combination of applied magnetic and electricfields can reveal a chirality-dependent nuclear magnetic resonance (NMR) signalwhich is essentially the NMR version of optical activity. The combination ofchiral sensitivity with the chemical specificity of NMR spectroscopy would be amajor step forward in the field of chiral analysis. I also extend these ideasand show that molecular chirality is not strictly necessary to observe thesesignals, but rather a breaking of exchange symmetry between two coupled nuclei.This symmetry breaking can arise from molecular geometry (as in the case ofchirality) or from a parity violating contribution to the J-coupling. I presentestimates of the parity-violationg J-coupling for the diatomic molecules 1H19Fand 205Tl19F and discuss the prospects of atomic vapor magnetometerdetected zero-field NMR as a search for molecular parity violation.

Jonathan King, UC Berkeley