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MO: Fachverband Molekülphysik
MO 14: Cold Molecules 2
MO 14.2: Vortrag
Donnerstag, 20. März 2014, 10:45–11:00, BEBEL HS213
Spatially separating para and ortho water – fully quantum state selected samples of gas-phase molecules — •Daniel Horke1, Yuan-Pin Chang1, and Jochen Küpper1,2,3 — 1Center for Free-Electron Laser Science, DESY — 2Department of Physics, University of Hamburg — 3Center for Ultrafast Imaging, University of Hamburg
Different molecular species present in supersonically expanded molecular beams can be separated using the electrostatic deflector, including different conformers [1], cluster stoichiometries [2], and individual quantum states of small linear rotor molecules [3].
We demonstrated the production of single quantum states of water in the gas-phase, and separation of its nuclear spin isomers. The spins of the two equivalent protons in water lead to two distinct nuclear spin states – para and ortho. According to the Pauli principle, the overall wavefunction of water must by antisymmetric for the exchange of the two protons. Due to the exact symmetry properties of water, para and ortho spin states correspond to distinct rovibronic states. We demonstrated the production of a cold beam of water, with >95% of population in the two absolute ground states. We spatially separated these using strong inhomogeneous electric fields. This is the first time pure samples of either spin isomer of water were produced.
[1] F. Filsinger et al, Phys. Rev. Lett. 100, 133003; ibid, Angew. Chem. Int. Ed. 48, 6900; Y.P. Chang et al, Science 342, 98
[2] S. Trippel et al, Phys. Rev. A 86, 033202
[3] J. H. Nielsen et al, Phys. Chem. Chem. Phys. 13, 18971