EUROISMAR 2019

Computation of conventional NMR parameters has become routine. There remain, however, interesting physics to be explored. I introduce four topics of this kind.
For the first time, measured $J$-coupling over a van der Waals (vdW) bond, between ¹²⁹Xe and ³He in a gas-phase nuclear spin co-magnetometer, can be directly compared with quantitative calculations [1]. The latter involve the second virial coefficient of $J$(¹²⁹Xe-³He) from relativistic potential energy and $J$-coupling curves.
NMR parameters are magnetic field-dependent. So far, only $B$₀-dependent ¹³¹Xe quadrupole coupling has been found [2]. Experiments on Co(acac)₃ -complex [3], where low-lying d-d excitations render the ⁵⁹Co shift significantly $B$₀-dependent, are compared with non-linear response theory for the leading $O$($B$₀²) terms [4].
Nucleus-specific information can be obtained from changes in light beam polarisation due to interaction with nuclear spins [5]. We predict nuclear spin-induced magnetochiral birefringence and dichroism, as possible reporters of chirality via different indices of refraction when light propagates parallel and antiparallel with spin magnetisation [6].
In a multi-scale study of spin-exchange optical pumping [7], Rb-Xe collisions are extracted from molecular dynamics and analysed using spin dynamics driven by a quantum-chemical spin Hamiltonian. We reproduce the roles of binary collisions and long-lived vdW complexes and, for the first time, see step-wise build-up of ¹²⁹Xe polarisation upon vdW oscillations.
[1] J. Vaara, M. V. Romalis, Phys. Rev. A, in press (2019)
[2] T. Meersmann, M. Haake, Phys. Rev. Lett. 81, 1211 (1998)
[3] A. M. Kantola, P. Lantto, I. Heinmaa, J. Vaara, J. Jokisaari, in preparation (2019)
[4] P. Manninen, J. Vaara, Phys. Rev. A 69, 022503 (2004)
[5] I. M. Savukov, S.-K. Lee, and M. V. Romalis, Nature 442, 1021 (2006)
[6] L.-j. Fu, J. Cukras, D. Fedotov, S. Coriani, J. Vaara, in preparation (2019)
[7] J. Rantaharju, M. Hanni, J. Vaara, submitted (2019)