Speaker
Alec Owens
(CFEL, Universität Hamburg, The Hamburg Centre for Ultrafast Imaging)
Description
Chirality is conventionally associated with a chemical or optical property of a molecule being in either of its two enantiomeric (mirror-image) forms. In a more general sense, chirality is determined by the time and space inversion (PT) symmetry of the system. Chiral molecules are ‘born’ to be so, owing to their quasi-rigid spatially enantiomorphic geometrical structures with high potential energy barriers between the enantiomers.
That said, it is possible to induce and modulate chirality in statically non-chiral molecules. For example, by forcing a molecule to rotate coherently in one direction, i.e., to possess a well-defined helicity, we can create a chiral entity. Phosphine (PH3) is an excellent example: at high rotational excitation it forms well separated near degenerate rotational cluster states where the molecule undergoes stable rotation around one of its P-H bonds in a clockwise or anti-clockwise manner [1,2]. This is analogous to a system with static chirality: oppositely rotating forms are energetically indistinguishable from each other and are separated by a high (kinetic) energy barrier.
We will present robust, quantum mechanical simulations of the experimental methods for creating rotational cluster states in PH3 [3] (e.g., using an optical centrifuge [4,5]), techniques for spatial separation [6] of the dynamically chiral enantiomers, as well as perspectives for detecting chirality using modern experiments [7,8,9].
[1] P. R. Bunker, P. Jensen, J. Mol. Spectrosc. 228, 640 (2004).
[2] S. N. Yurchenko, W. Thiel, S. Patchkovskii, P. Jensen, Phys. Chem. Chem. Phys. 7, 573 (2005).
[3] A. Owens, A. Yachmenev, J. Kupper, in preparation.
[4] J. Karczemarek, J. Wright, P. Corkum, M. Ivanov, Phys. Rev. Lett. 82, 3420 (1999).
[5] A. Korobenko, V. Milner, Phys. Rev. Lett. 116, 183001 (2016).
[6] Y.-P. Chang, D. A. Horke, S. Trippel, J. Kupper, Int. Rev. Phys. Chem. 34, 557 (2015).
[7] A. A. Lutman et al., Nat. Photon. 10, 468 (2016).
[8] A. Yachmenev, S. N. Yurchenko, Phys. Rev. Lett. 117, 033001 (2016).
[9] M. H. M. Janssen, I. Powis, Phys. Chem. Chem. Phys. 16, 856 (2014).
Authors
Alec Owens
(CFEL, Universität Hamburg, The Hamburg Centre for Ultrafast Imaging)
Andrey Yachmenev
(CFEL, DESY Hamburg; Universität Hamburg, The Hamburg Centre for Ultrafast Imaging)
Prof.
Jochen Küpper
(Center for Free Electron Laser Science, DESY and Universität Hamburg)
