25-30 August 2019
Henry Ford Building
Europe/Berlin timezone

Adventures with Long-Lived States

26 Aug 2019, 08:40
40m
Max Kade Auditorium (Henry Ford Building)

Max Kade Auditorium

Henry Ford Building

Prize lecture Spin physics Prize Lectures

Speaker

Prof. Malcolm Levitt (University of Southampton)

Description

Long-lived states are particular configurations of nuclear spins which are well-protected against relaxation mechanisms. These configurations appear as particular terms in the spin density operator associated with unusually slow decay rate constants. A seminal example arises in systems of homonuclear spin-1/2 pairs in solution. Singlet order, meaning a population imbalance between the singlet state and the triplet states, is protected against relaxation by the homonuclear dipole-dipole coupling between the two spins, and often has a decay time constant which exceeds T1 by a large factor. In one case, a singlet order lifetime exceeding 1 hour has been observed for a pair of 13C nuclei, even though T1 is about 1 minute under the same conditions.

Our group, and our collaborators, have been enjoying numerous adventures in the world of long-lived states. I will report on some of the following topics:

  • using group theory to count and derive long-lived states
  • using long-lived states to pump up the nuclear magnetization
  • long-lived coherences, including the observation of coherent oscillations proceeding for tens of minutes - even when the sample is removed from the magnet
  • relaxation mechanisms for long-lived states, including scalar relaxation in deuterated molecules
  • new molecular systems supporting long-lived states
  • a new master equation for spin dynamics far from equilibrium
  • hyperpolarized long-lived singlet order generated by parahydrogen reactions: geminal-PHIP and trans-PHIP
  • spin-isomer conversion of molecules trapped inside fullerenes

Primary author

Prof. Malcolm Levitt (University of Southampton)

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